wip adapt lobby to be functional in an iframe

Add a prototype setup that uses OrbStack as the local Kubernetes
provider on macOS, aiming to save a few GB of RAM compared to the
current stack.

The script has been tested locally but was mostly built through vibe
coding, so it has not been thoroughly reviewed yet.

Follow-ups to look into:

* Simplify the ingress and CoreDNS setup if possible.
* Wire up a way to run tests and lint against the Tilt stack.

Makefile

@@ -389,6 +389,12 @@ build-k8s-cluster: \
     ./bin/start-kind.sh
 .PHONY: build-k8s-cluster
 
+build-k8s-cluster-orbstack: ## setup the kubernetes environment on OrbStack's built-in cluster (macOS)
+build-k8s-cluster-orbstack: \
+    env.d/development/kube-secret
+	./bin/start-orbstack.sh
+.PHONY: build-k8s-cluster-orbstack
+
 start-tilt-keycloak: ## start the kubernetes cluster using kind, without Pro Connect for authentication, use keycloak
 	DEV_ENV=dev-keycloak tilt up --namespace=meet -f ./bin/Tiltfile
 .PHONY: build-k8s-cluster

bin/Tiltfile

@@ -1,5 +1,11 @@
 load('ext://uibutton', 'cmd_button', 'bool_input', 'location')
 load('ext://namespace', 'namespace_create', 'namespace_inject')
+
+# OrbStack's built-in cluster (macOS) is a supported alternative to kind.
+# Recent Tilt versions (>= 0.33) detect it as a local dev cluster; this is
+# a no-op for kind and a safety net for older Tilt versions.
+allow_k8s_contexts('orbstack')
+
 namespace_create('meet')
 
 DEV_ENV = os.getenv('DEV_ENV', 'dev-keycloak')

bin/start-orbstack.sh

@@ -0,0 +1,182 @@
+#!/usr/bin/env bash
+#
+# Bootstrap the local dev environment on OrbStack's built-in Kubernetes
+# cluster (macOS) instead of kind.
+#
+# This replicates what bin/start-kind.sh (numerique-gouv/tools
+# kind/create_cluster.sh) provides, minus what OrbStack makes unnecessary:
+#   - no kind cluster: OrbStack ships a lightweight single-node cluster
+#   - no local registry (kind-registry): OrbStack's cluster shares the
+#     Docker image store, so images built by Tilt are directly visible
+#     to pods. Tilt detects the "orbstack" context as a local cluster
+#     and skips pushing images entirely.
+#
+# Requirements: OrbStack (with Kubernetes enabled), kubectl, mkcert, curl.
+set -o errexit
+
+APPLICATION=${1:-meet}
+CONTEXT="orbstack"
+
+echo "0. Check OrbStack Kubernetes is available"
+if ! command -v mkcert >/dev/null 2>&1; then
+  echo "❌ mkcert is not installed. Install it first: brew install mkcert"
+  exit 1
+fi
+if ! kubectl config get-contexts -o name | grep -qx "${CONTEXT}"; then
+  echo "Context '${CONTEXT}' not found. Trying to start OrbStack Kubernetes..."
+  if command -v orb >/dev/null 2>&1; then
+    orb start k8s
+  else
+    echo "❌ Enable Kubernetes in OrbStack (Settings > Kubernetes) and retry."
+    exit 1
+  fi
+fi
+kubectl config use-context "${CONTEXT}"
+
+echo "0b. Check ports 80/443 are free on localhost"
+# OrbStack forwards LoadBalancer service ports to 127.0.0.1. If the kind
+# cluster is still running, its docker proxy already holds 80/443.
+# Skip the check if ingress-nginx is already installed here: in that case
+# the listener on 80/443 is our own LoadBalancer.
+if ! kubectl -n ingress-nginx get deployment ingress-nginx-controller >/dev/null 2>&1; then
+  for port in 80 443; do
+    if lsof -nP -iTCP:"${port}" -sTCP:LISTEN >/dev/null 2>&1; then
+      echo "❌ Port ${port} is already in use on the host."
+      echo "   If the kind cluster is running, delete it first:"
+      echo "     kind delete cluster --name suite"
+      exit 1
+    fi
+  done
+fi
+
+echo "1. Create ca"
+CURRENT_DIR=$(pwd)
+mkcert -install
+cd /tmp
+mkcert "127.0.0.1.nip.io" "*.127.0.0.1.nip.io"
+cd "${CURRENT_DIR}"
+
+echo "2. Install ingress-nginx (cloud provider: LoadBalancer service)"
+# OrbStack exposes LoadBalancer services on 127.0.0.1, so the cloud
+# manifest replaces kind's hostPort-based deploy. Every sub-step below is
+# guarded individually so the script is safe to re-run after a partial
+# failure (unlike the upstream kind script, which guards the whole block
+# on namespace existence).
+
+# Make sure no stale registry configmap tells Tilt to push to localhost:5001
+# (there is no registry on OrbStack).
+kubectl -n kube-public delete configmap local-registry-hosting --ignore-not-found
+
+if ! kubectl -n ingress-nginx get deployment ingress-nginx-controller >/dev/null 2>&1; then
+  kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/main/deploy/static/provider/cloud/deploy.yaml
+fi
+if ! kubectl -n ingress-nginx get deployment nginx-errors >/dev/null 2>&1; then
+  kubectl apply -n ingress-nginx -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/refs/heads/main/docs/examples/customization/custom-errors/custom-default-backend.yaml
+fi
+kubectl -n ingress-nginx create secret tls mkcert --key /tmp/127.0.0.1.nip.io+1-key.pem --cert /tmp/127.0.0.1.nip.io+1.pem || echo ok
+
+# The meet charts render Ingresses without ingressClassName. The kind
+# provider manifest handles this via --watch-ingress-without-class=true;
+# the cloud manifest does not, so add it here (otherwise: 404 everywhere).
+if ! kubectl -n ingress-nginx get deployment ingress-nginx-controller -o jsonpath='{.spec.template.spec.containers[0].args}' | grep -q 'watch-ingress-without-class'; then
+  kubectl -n ingress-nginx patch deployments.apps ingress-nginx-controller --type 'json' -p '[{"op": "add", "path": "/spec/template/spec/containers/0/args/-", "value":"--watch-ingress-without-class=true"},{"op": "add", "path": "/spec/template/spec/containers/0/args/-", "value":"--default-ssl-certificate=ingress-nginx/mkcert"},{"op": "add", "path": "/spec/template/spec/containers/0/args/-", "value":"--default-backend-service=ingress-nginx/nginx-errors"}
+]'
+fi
+if ! kubectl -n ingress-nginx get deployment nginx-errors -o jsonpath='{.spec.template.spec.containers[0].image}' | grep -q 'error-pages'; then
+  kubectl -n ingress-nginx patch deployment nginx-errors --type=json -p='[
+  {"op": "replace", "path": "/spec/template/spec/containers/0/image", "value": "ghcr.io/tarampampam/error-pages:3.3.0"},
+  {"op": "add", "path": "/spec/template/spec/containers/0/env", "value": [{"name": "TEMPLATE_NAME", "value": "ghost"}, {"name": "SHOW_DETAILS", "value": "false"}, {"name": "SEND_SAME_HTTP_CODE", "value": "true"}]}
+]'
+fi
+cat <<EOF | kubectl apply -n ingress-nginx -f -
+  apiVersion: v1
+  data:
+    allow-snippet-annotations: "true"
+    annotations-risk-level: Critical
+    custom-http-errors: 500,501,502,503,504
+  kind: ConfigMap
+  metadata:
+    name: ingress-nginx-controller
+    namespace: ingress-nginx
+EOF
+
+echo "2b. Wait for the ingress controller to be ready"
+kubectl -n ingress-nginx rollout status deployment/ingress-nginx-controller --timeout=180s
+
+echo "3. Patch CoreDNS so in-cluster pods resolve *.127.0.0.1.nip.io to the ingress"
+# nip.io resolves to 127.0.0.1, which inside a pod is the pod itself.
+# Rewrite these names to the ingress-nginx service, like the kind setup does.
+# Unlike kind, we amend OrbStack's existing Corefile instead of replacing it.
+if ! kubectl -n kube-system get configmap coredns -o jsonpath='{.data.Corefile}' | grep -q '127\.0\.0\.1\.nip\.io'; then
+  kubectl -n kube-system get configmap coredns -o jsonpath='{.data.Corefile}' \
+    | awk '/forward \./ && !done { print "    rewrite stop {"; print "      name regex (.*).127.0.0.1.nip.io ingress-nginx-controller.ingress-nginx.svc.cluster.local answer auto"; print "    }"; done=1 } { print }' \
+    >/tmp/Corefile.orbstack
+  kubectl -n kube-system create configmap coredns --from-file=Corefile=/tmp/Corefile.orbstack --dry-run=client -o yaml | kubectl apply -f -
+  kubectl -n kube-system rollout restart deployments/coredns
+fi
+
+if ! kubectl get ns "${APPLICATION}" >/dev/null 2>&1; then
+  echo "4. Setup namespace"
+  kubectl create ns "${APPLICATION}"
+fi
+kubectl config set-context --current --namespace="${APPLICATION}"
+kubectl -n "${APPLICATION}" create secret generic mkcert --from-file=rootCA.pem="$(mkcert -CAROOT)/rootCA.pem" || echo ok
+
+if ! kubectl get configmap certifi -n "${APPLICATION}" >/dev/null 2>&1; then
+  echo "5. Inject our custom CA in a configmap for certifi"
+  curl https://raw.githubusercontent.com/certifi/python-certifi/refs/heads/master/certifi/cacert.pem -o /tmp/cacert.pem
+  cat "$(mkcert -CAROOT)/rootCA.pem" >>/tmp/cacert.pem
+  kubectl -n "${APPLICATION}" create configmap certifi --from-file=cacert.pem=/tmp/cacert.pem
+  kubectl -n "${APPLICATION}" create secret generic certifi --from-file=/tmp/cacert.pem || echo ok
+fi
+
+echo "5b. Smoke test: the ingress chain answers on https://127.0.0.1"
+# Before Tilt deploys the app this returns the styled 404 from the default
+# backend — that still proves LB -> controller works. 000 means the
+# LoadBalancer is not bound to localhost.
+HTTP_CODE=$(curl -sk -o /dev/null -w '%{http_code}' --max-time 10 https://127.0.0.1/ || true)
+if [ "${HTTP_CODE}" = "000" ]; then
+  echo "⚠️  Nothing answered on https://127.0.0.1 — check the LoadBalancer:"
+  echo "    kubectl -n ingress-nginx get svc ingress-nginx-controller"
+else
+  echo "✅ Ingress reachable (HTTP ${HTTP_CODE})"
+fi
+
+echo "6. Check pod readiness across all namespaces..."
+
+sleep_interval=10
+
+echo "Initial wait time: $((sleep_interval * 2)) seconds…"
+sleep $((sleep_interval * 2))
+
+check_pods_ready() {
+    local max_attempts=60  # Maximum number of attempts (10 minutes with 10s intervals)
+    local attempt=1
+
+    while [ $attempt -le $max_attempts ]; do
+        echo "Attempt $attempt/$max_attempts - Checking pod status..."
+
+        not_ready_count=$( kubectl get po -A --no-headers | grep -v -E "Running|Completed"| wc -l | tr -d ' ')
+
+        if [ "$not_ready_count" -eq 0 ]; then
+            echo "✅ All pods are ready!"
+            return 0
+        else
+            echo "⏳ $not_ready_count pod(s) still not ready. Waiting $sleep_interval seconds…"
+            sleep $sleep_interval
+            ((attempt++))
+        fi
+    done
+
+    echo "❌ Timeout: Some pods are still not ready after 10 minutes"
+    echo "Final pod status:"
+    kubectl get po -A
+    return 1
+}
+
+if check_pods_ready; then
+    echo "🎉 Cluster is fully ready!"
+else
+    echo "⚠️  Some pods may need manual intervention"
+    exit 1
+fi

docs/developping_locally.md

@@ -143,3 +143,24 @@ $ make start-tilt-keycloak
 ```
 
 Monitor Tilt’s progress at [http://localhost:10350/](http://localhost:10350/). After Tilt actions finish, you can access the app at [https://meet.127.0.0.1.nip.io/](https://meet.127.0.0.1.nip.io/).
+
+### Alternative: OrbStack's built-in Kubernetes (macOS)
+
+If you use [OrbStack](https://orbstack.dev/) on macOS, you can run the stack on its built-in Kubernetes cluster instead of kind. It uses noticeably less RAM (no nested kubeadm node container) and no local registry is needed: OrbStack's cluster shares the Docker image store, so Tilt uses images directly without pushing.
+
+Enable Kubernetes in OrbStack (Settings > Kubernetes), then:
+
+```shellscript
+$ make build-k8s-cluster-orbstack
+```
+
+This installs ingress-nginx (exposed by OrbStack on `127.0.0.1:80/443`), the mkcert TLS certificates, and the CoreDNS rewrite for `*.127.0.0.1.nip.io`, then you start Tilt as usual:
+
+```shellscript
+$ make start-tilt-keycloak
+```
+
+Notes:
+- Ports 80/443 must be free: delete the kind cluster first if you used it (`kind delete cluster --name suite`).
+- If you "Reset Kubernetes" in OrbStack, re-run `make build-k8s-cluster-orbstack`.
+- kind remains the reference setup (matches CI and lets you pin the Kubernetes version).

src/backend/core/api/feature_flag.py

@@ -16,6 +16,7 @@ class FeatureFlag:
         "file_upload": "FILE_UPLOAD_ENABLED",
         "addons": "ADDONS_ENABLED",
         "application": "APPLICATION_ENABLED",
+        "user_access_token": "USER_ACCESS_TOKEN_ENABLED",
     }
 
     @classmethod

src/backend/core/api/serializers.py

@@ -273,6 +273,11 @@ class RequestEntrySerializer(BaseValidationOnlySerializer):
     """Validate request entry data."""
 
     username = serializers.CharField(required=True)
+    participant_id = serializers.UUIDField(required=False, allow_null=True)
+
+    def validate_participant_id(self, value):
+        """The id is a bearer credential: never trusted, only looked up."""
+        return str(value) if value else None
 
 
 class ParticipantEntrySerializer(BaseValidationOnlySerializer):
@@ -580,3 +585,25 @@ class ExternalProcessEventSerializer(BaseValidationOnlySerializer):
     # useless bad requests
     type = serializers.CharField(required=False, allow_null=True, allow_blank=True)
     status = serializers.CharField(required=False, allow_null=True, allow_blank=True)
+
+
+class TransitCodeSerializer(BaseValidationOnlySerializer):
+    """Validate the single-use transit code sent to the exchange endpoint."""
+
+    # todo if I can pass the max length directly to the char field
+    code = serializers.CharField(max_length=255, trim_whitespace=True)
+
+    def validate_code(self, value):
+        """Reject codes whose length cannot match a generated one.
+
+        `secrets.token_urlsafe(nbytes)` produces (4 * nbytes + 2) // 3
+        url-safe characters. Checking the length against the configured
+        TRANSIT_CODE_NBYTES makes malformed codes fail fast with a 400,
+        before any cache lookup.
+        """
+        expected_length = (4 * settings.TRANSIT_CODE_NBYTES + 2) // 3
+
+        if len(value) != expected_length:
+            raise serializers.ValidationError("Invalid transit code format.")
+
+        return value

src/backend/core/api/throttling.py

@@ -1,11 +1,11 @@
 """Throttling modules for the API."""
 
-from django.conf import settings
-
 from lasuite.drf.throttling import MonitoredThrottleMixin
 from rest_framework.throttling import AnonRateThrottle, UserRateThrottle
 from sentry_sdk import capture_message
 
+from . import serializers
+
 
 def sentry_monitoring_throttle_failure(message):
     """Log when a failure occurs to detect rate limiting issues."""
@@ -42,13 +42,14 @@ class RequestEntryAnonRateThrottle(MonitoredAnonRateThrottle):
     def get_cache_key(self, request, view):
         """Use the lobby participant cookie ID as the throttle cache key.
 
-        Only throttle if a cookie is already set. If no cookie exists yet,
-        return None to skip throttling — the cookie will be set on the first
-        response, and throttling will apply from the second request onward.
+        Only throttle requests carrying a participant identifier. The
+        identifier is returned by the first request-entry response and
+        echoed back by the client from the second request onward, which is
+        when throttling starts applying.
 
-        Keying on the cookie rather than the IP address prevents penalising
-        multiple users behind the same NAT/proxy, and is consistent with how
-        LobbyService identifies participants.
+        Keying on the identifier rather than the IP address prevents
+        penalising multiple users behind the same NAT/proxy, and is
+        consistent with how the lobby identifies participants.
 
         Note: as per DRF documentation, application-level throttling is not a
         security measure against brute-force or DoS attacks. This throttle exists
@@ -58,10 +59,14 @@ class RequestEntryAnonRateThrottle(MonitoredAnonRateThrottle):
         if request.user and request.user.is_authenticated:
             return None  # Only throttle unauthenticated requests.
 
-        participant_id = request.COOKIES.get(settings.LOBBY_COOKIE_NAME)
+        serializer = serializers.RequestEntrySerializer(data=request.data)
+        if not serializer.is_valid():
+            return None
 
-        if participant_id is None:
-            return None  # No throttling for cookieless requests
+        participant_id = serializer.validated_data.get("participant_id")
+
+        if not participant_id:
+            return None  # No throttling for unidentified requests
 
         return self.cache_format % {
             "scope": self.scope,
@@ -73,3 +78,14 @@ class CreationCallbackAnonRateThrottle(MonitoredAnonRateThrottle):
     """Throttle Anonymous user requesting room generation callback"""
 
     scope = "creation_callback"
+
+
+class ExchangeAccessTokenAnonRateThrottle(MonitoredAnonRateThrottle):
+    """Throttle anonymous transit code exchange attempts.
+
+    Abuse mitigation only, not a security boundary: DRF throttling is
+    best-effort. The security of the exchange rests on the codes'
+    entropy and single use.
+    """
+
+    scope = "exchange_access_token"

src/backend/core/api/viewsets.py

@@ -69,6 +69,7 @@ from core.recording.worker.mediator import (
     WorkerServiceMediator,
 )
 from core.services.invitation import InvitationService
+from core.services.jwt_token import JwtTokenService
 from core.services.livekit_events import (
     LiveKitEventsService,
     LiveKitWebhookError,
@@ -93,6 +94,7 @@ from core.services.room_roles import (
     RoomRoleService,
 )
 from core.services.subtitle import SubtitleException, SubtitleService
+from core.services.transit_code import TransitCodeService
 from core.tasks.file import process_file_deletion
 
 from ..authentication.livekit import LiveKitTokenAuthentication
@@ -229,6 +231,76 @@ class UserViewSet(
             self.serializer_class(request.user, context=context).data
         )
 
+    @decorators.action(
+        detail=False,
+        methods=["post"],
+        url_path="exchange-access-token",
+        permission_classes=[],
+        throttle_classes=[throttling.ExchangeAccessTokenAnonRateThrottle],
+    )
+    @FeatureFlag.require("user_access_token")
+    def exchange_access_token(self, request):
+        """Exchange a single-use transit code for a user access token.
+
+        The endpoint is unauthenticated: the transit code itself, an opaque
+        random string obtained through the external API and delivered to
+        the embedded frontend via a URL fragment, is the credential. Each
+        code can be exchanged exactly once (consuming it deletes it from
+        the cache); replaying a consumed code is denied and logged.
+
+        The issued JWT authenticates the user the code was minted for on
+        the whole core API, exactly like a session cookie would (similar
+        to lib-jitsi-meet's token authentication), and never appears in
+        any URL. Role-based permissions apply unchanged.
+        """
+        serializer = serializers.TransitCodeSerializer(data=request.data)
+        serializer.is_valid(raise_exception=True)
+
+        code_data = TransitCodeService().consume_code(serializer.validated_data["code"])
+
+        if code_data is None:
+            logger.warning("Invalid, expired or already used transit code")
+            raise drf_exceptions.PermissionDenied(
+                "Invalid, expired or already used transit code."
+            )
+
+        # Re-check the user at exchange time so that a deactivation after
+        # the transit code was minted is taken into account.
+        try:
+            user = models.User.objects.get(id=code_data["user_id"], is_active=True)
+        except models.User.DoesNotExist as excpt:
+            raise drf_exceptions.PermissionDenied(
+                "This account can no longer access the application."
+            ) from excpt
+
+        token_service = JwtTokenService(
+            secret_key=settings.USER_ACCESS_TOKEN_SECRET_KEY,
+            algorithm=settings.USER_ACCESS_TOKEN_ALG,
+            issuer=settings.USER_ACCESS_TOKEN_ISSUER,
+            audience=settings.USER_ACCESS_TOKEN_AUDIENCE,
+            expiration_seconds=settings.USER_ACCESS_TOKEN_TTL,
+            token_type=settings.USER_ACCESS_TOKEN_TYPE,
+        )
+
+        # todo - discuss wether it's the relevant scope
+        data = token_service.generate_jwt(
+            user,
+            "user:access",
+            {
+                "token_type": "user_access",
+                "client_id": code_data.get("client_id", "unknown"),
+            },
+        )
+
+        # Log for auditing
+        logger.info(
+            "User access token issued from transit code: user_id=%s, client_id=%s",
+            user.id,
+            code_data.get("client_id", "unknown"),
+        )
+
+        return drf_response.Response(data)
+
 
 class RoomViewSet(
     mixins.CreateModelMixin,
@@ -499,10 +571,7 @@ class RoomViewSet(
             request=request,
             **serializer.validated_data,
         )
-        response = drf_response.Response({**participant.to_dict(), "livekit": livekit})
-        lobby_service.prepare_response(response, participant.id)
-
-        return response
+        return drf_response.Response({**participant.to_dict(), "livekit": livekit})
 
     @decorators.action(
         detail=True,

src/backend/core/authentication/livekit.py

@@ -9,6 +9,8 @@ from rest_framework import authentication, exceptions
 
 UserModel = get_user_model()
 
+LIVEKIT_AUTH_SCHEME = "X-LiveKit-Token"
+
 
 class LiveKitTokenAuthentication(authentication.BaseAuthentication):
     """Authenticate using LiveKit token and load the associated Django user."""
@@ -20,9 +22,14 @@ class LiveKitTokenAuthentication(authentication.BaseAuthentication):
             return None  # No authentication attempted
 
         parts = auth_header.split()
-        if len(parts) != 2 or parts[0].lower() != "bearer":
+        if not parts or parts[0].lower() != LIVEKIT_AUTH_SCHEME.lower():
+            # Not our scheme (e.g. "Bearer <user access token>"): defer, another
+            # backend may recognize it.
+            return None
+
+        if len(parts) != 2:
             raise exceptions.AuthenticationFailed(
-                "Authorization header must be: Bearer <token>"
+                f"Authorization header must be: {LIVEKIT_AUTH_SCHEME} <token>"
             )
 
         token = parts[1]

src/backend/core/authentication/user_token.py

@@ -0,0 +1,71 @@
+"""User access JWT authentication for the Meet core API.
+
+Allows an embedded frontend (e.g. rendered in an iframe, where third-party
+session cookies are blocked) to authenticate requests on the core API with
+a JWT, obtained by exchanging a single-use transit code (see
+core.services.transit_code and the users exchange-access-token endpoint)
+and passed as a Bearer header. The JWT itself never appears in any URL.
+
+Similar to lib-jitsi-meet's token authentication, the token is bound to a
+user, not to a resource: once authenticated, the request is treated
+exactly like a session-authenticated one, and the existing role-based
+permissions apply unchanged.
+"""
+
+import logging
+
+from django.conf import settings
+
+from rest_framework import exceptions
+
+from core.external_api.authentication import BaseJWTAuthentication
+
+logger = logging.getLogger(__name__)
+
+USER_ACCESS_TOKEN_TYPE_CLAIM = "user_access"  # noqa: S105
+
+
+class UserAccessJWTAuthentication(BaseJWTAuthentication):
+    """JWT authentication for user access tokens.
+
+    Validates user access tokens issued by the users exchange-access-token
+    endpoint and authenticates the user they were issued for. A bearer
+    token that does not verify against the user access token secret is
+    deferred to the next authentication backend; a token that does verify
+    but carries wrong claims is rejected.
+
+    When the feature is disabled (USER_ACCESS_TOKEN_ENABLED=False), the
+    backend is entirely inert: `BaseJWTAuthentication.authenticate`
+    returns None before reading the Authorization header, deferring every
+    request to the next authentication backend.
+    """
+
+    def __init__(self):
+        """Initialize the backend with user access token settings."""
+        super().__init__(
+            secret_key=settings.USER_ACCESS_TOKEN_SECRET_KEY,
+            algorithm=settings.USER_ACCESS_TOKEN_ALG,
+            issuer=settings.USER_ACCESS_TOKEN_ISSUER,
+            audience=settings.USER_ACCESS_TOKEN_AUDIENCE,
+            expiration_seconds=settings.USER_ACCESS_TOKEN_TTL,
+            token_type=settings.USER_ACCESS_TOKEN_TYPE,
+            is_enabled=settings.USER_ACCESS_TOKEN_ENABLED,
+        )
+
+    def validate_payload(self, payload):
+        """Validate the token type and the issuance-audit claim.
+
+        Raises:
+            AuthenticationFailed: If the token verified against the user
+                access token secret but does not carry the expected claims.
+        """
+        if payload.get("token_type") != USER_ACCESS_TOKEN_TYPE_CLAIM:
+            logger.warning("Wrong 'token_type' in user access token payload")
+            raise exceptions.AuthenticationFailed("Invalid token type.")
+
+        # Every token we issue carries the client_id of the application the
+        # transit code was minted for: its absence means the token does not
+        # come from the exchange endpoint.
+        if not payload.get("client_id"):
+            logger.warning("Missing 'client_id' in user access token payload")
+            raise exceptions.AuthenticationFailed("Invalid token claims.")

src/backend/core/external_api/permissions.py

@@ -86,6 +86,14 @@ class HasRequiredRoomScope(BaseScopePermission):
     }
 
 
+class HasRequiredUserScope(BaseScopePermission):
+    """Scope-based permissions for the external user endpoints."""
+
+    scope_map = {
+        "generate_transit_code": models.ApplicationScope.USERS_SESSION,
+    }
+
+
 class RoomPermissions(permissions.BasePermission):
     """Permissions applying to the room API endpoint."""
 

src/backend/core/external_api/viewsets.py

@@ -22,6 +22,7 @@ from rest_framework import (
 from core import analytics, api, models
 from core.api.feature_flag import FeatureFlag
 from core.services.jwt_token import JwtTokenService
+from core.services.transit_code import TransitCodeService
 
 from ..services.provisional_user_service import (
     ProvisionalUserCreationDisabledError,
@@ -218,3 +219,62 @@ class RoomViewSet(
                 "$set": {"email": self.request.user.email},
             },
         )
+
+
+class UserViewSet(viewsets.GenericViewSet):
+    """Application-delegated API for user operations.
+
+    Provides JWT-authenticated access to user operations for external
+    applications acting on behalf of users. All operations are
+    scope-based. Meant to grow with the other user actions exposed to
+    third parties.
+
+    Supported operations:
+    - transit-code: Mint a single-use transit code for the delegated user
+      (requires 'users:session' scope)
+    """
+
+    authentication_classes = [
+        authentication.ApplicationJWTAuthentication,
+        ResourceServerAuthentication,
+    ]
+    permission_classes = [
+        api.permissions.IsAuthenticated & permissions.HasRequiredUserScope
+    ]
+
+    @decorators.action(
+        detail=False,
+        methods=["post"],
+        url_path="transit-code",
+        url_name="transit-code",
+    )
+    @FeatureFlag.require("user_access_token")
+    def generate_transit_code(self, request):
+        """Mint a transit code for the delegated user.
+
+        Returns a short-lived, single-use opaque code to pass to an embedded
+        frontend (e.g. via a URL fragment when cookies are unavailable). The
+        frontend exchanges it once on
+        POST /api/v1.0/users/exchange-access-token/ for a JWT access token,
+        equivalent to session-cookie authentication and never exposed in a URL.
+        """
+        auth_method = type(request.successful_authenticator).__name__
+        client_id = (request.auth or {}).get("client_id", "unknown")
+
+        code = TransitCodeService().create_code(request.user, client_id=client_id)
+
+        # Log for auditing
+        logger.info(
+            "Transit code issued: user_id=%s, client_id=%s, auth_method=%s",
+            request.user.id,
+            client_id,
+            auth_method,
+        )
+
+        return drf_response.Response(
+            {
+                "transit_code": code,
+                "expires_in": settings.TRANSIT_CODE_TTL,
+            },
+            status=drf_status.HTTP_200_OK,
+        )

src/backend/core/migrations/0022_alter_application_scopes.py

@@ -0,0 +1,19 @@
+# Generated by Django 5.2.14 on 2026-07-31 18:27
+
+import django.contrib.postgres.fields
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0021_recording_external_process_id_alter_recording_status'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='application',
+            name='scopes',
+            field=django.contrib.postgres.fields.ArrayField(base_field=models.CharField(choices=[('rooms:create', 'Create rooms'), ('rooms:list', 'List rooms'), ('rooms:retrieve', 'Retrieve room details'), ('rooms:update', 'Update rooms'), ('rooms:delete', 'Delete rooms'), ('users:session', 'Create user session tokens')], max_length=50), blank=True, default=list, size=None),
+        ),
+    ]

src/backend/core/models.py

@@ -769,6 +769,7 @@ class ApplicationScope(models.TextChoices):
     ROOMS_RETRIEVE = "rooms:retrieve", _("Retrieve room details")
     ROOMS_UPDATE = "rooms:update", _("Update rooms")
     ROOMS_DELETE = "rooms:delete", _("Delete rooms")
+    USERS_SESSION = "users:session", _("Create user session tokens")
 
 
 class Application(BaseModel):

src/backend/core/services/lobby.py

@@ -86,23 +86,6 @@ class LobbyService:
         """Generate cache key for participant(s) data."""
         return f"{settings.LOBBY_KEY_PREFIX}_{room_id!s}_{participant_id}"
 
-    @staticmethod
-    def _get_or_create_participant_id(request) -> str:
-        """Extract unique participant identifier from the request."""
-        return request.COOKIES.get(settings.LOBBY_COOKIE_NAME, str(uuid.uuid4()))
-
-    @staticmethod
-    def prepare_response(response, participant_id):
-        """Set participant cookie if needed."""
-        if not response.cookies.get(settings.LOBBY_COOKIE_NAME):
-            response.set_cookie(
-                key=settings.LOBBY_COOKIE_NAME,
-                value=participant_id,
-                httponly=True,
-                secure=True,
-                samesite="Lax",
-            )
-
     @staticmethod
     def can_bypass_lobby(room, user, role) -> bool:
         """Determines if a user can bypass the waiting lobby and join a room directly.
@@ -135,6 +118,7 @@ class LobbyService:
         room: models.Room,
         request,
         username: str,
+        participant_id: Optional[uuid.UUID] = None,
     ) -> Tuple[LobbyParticipant, Optional[Dict]]:
         """Request entry to a room for a participant.
 
@@ -149,22 +133,20 @@ class LobbyService:
         5. If denied, do nothing.
         """
 
-        participant_id = self._get_or_create_participant_id(request)
-        participant = self._get_participant(room.id, participant_id)
+        participant = None
+        if participant_id:
+            participant = self._get_participant(room.id, participant_id)
+
+        is_new_participant = participant is None
+        if is_new_participant:
+            participant = self._create_participant(room.id, username)
 
         room_id = str(room.id)
         user_role = room.get_role(request.user)
 
         if self.can_bypass_lobby(room=room, user=request.user, role=user_role):
-            if participant is None:
-                participant = LobbyParticipant(
-                    status=LobbyParticipantStatus.ACCEPTED,
-                    username=username,
-                    id=participant_id,
-                    color=utils.generate_color(participant_id),
-                )
-            else:
-                participant.status = LobbyParticipantStatus.ACCEPTED
+            participant.status = LobbyParticipantStatus.ACCEPTED
+            self._save_participant(room.id, participant)
 
             livekit_config = utils.generate_livekit_config(
                 room_id=room_id,
@@ -172,18 +154,18 @@ class LobbyService:
                 username=username,
                 color=participant.color,
                 configuration=room.configuration,
-                participant_id=participant_id,
+                participant_id=participant.id,
                 role=user_role,
             )
             return participant, livekit_config
 
         livekit_config = None
 
-        if participant is None:
-            participant = self.enter(room.id, participant_id, username)
+        if is_new_participant:
+            self._notify_entry_request(room_id)
 
         elif participant.status == LobbyParticipantStatus.WAITING:
-            self.refresh_waiting_status(room.id, participant_id)
+            self.refresh_waiting_status(room.id, participant.id)
 
         elif participant.status == LobbyParticipantStatus.ACCEPTED:
             # wrongly named, contains access token to join a room
@@ -193,7 +175,7 @@ class LobbyService:
                 username=username,
                 color=participant.color,
                 configuration=room.configuration,
-                participant_id=participant_id,
+                participant_id=participant.id,
                 role=user_role,
             )
 
@@ -210,27 +192,36 @@ class LobbyService:
             self._get_cache_key(room_id, participant_id), settings.LOBBY_WAITING_TIMEOUT
         )
 
-    def enter(
-        self, room_id: UUID, participant_id: str, username: str
-    ) -> LobbyParticipant:
-        """Add participant to waiting lobby.
+    def _create_participant(self, room_id: UUID, username: str) -> LobbyParticipant:
+        """Create and persist a new waiting participant.
 
-        Create a new participant entry in waiting status and notify room
-        participants of the new entry request.
+        Participant identifiers are minted here, server-side, exclusively.
         """
-
-        color = utils.generate_color(participant_id)
-
+        participant_id = str(uuid.uuid4())
         participant = LobbyParticipant(
             status=LobbyParticipantStatus.WAITING,
             username=username,
             id=participant_id,
-            color=color,
+            color=utils.generate_color(participant_id),
+        )
+        self._save_participant(room_id, participant)
+
+        return participant
+
+    def _save_participant(self, room_id: UUID, participant: LobbyParticipant):
+        """Persist a participant in the room's lobby."""
+        cache.set(
+            self._get_cache_key(room_id, participant.id),
+            participant.to_dict(),
+            timeout=settings.LOBBY_WAITING_TIMEOUT,
         )
 
+    @staticmethod
+    def _notify_entry_request(room_id: str):
+        """Notify room participants of a new entry request."""
         try:
             utils.notify_participants(
-                room_name=str(room_id),
+                room_name=room_id,
                 notification_data={
                     "type": settings.LOBBY_NOTIFICATION_TYPE,
                 },
@@ -239,15 +230,6 @@ class LobbyService:
             # If room not created yet, there is no participants to notify
             logger.exception("Failed to notify room participants")
 
-        cache_key = self._get_cache_key(room_id, participant_id)
-        cache.set(
-            cache_key,
-            participant.to_dict(),
-            timeout=settings.LOBBY_WAITING_TIMEOUT,
-        )
-
-        return participant
-
     def _get_participant(
         self, room_id: UUID, participant_id: str
     ) -> Optional[LobbyParticipant]:

src/backend/core/services/transit_code.py

@@ -0,0 +1,74 @@
+"""Service handling the lifecycle of transit codes.
+
+A transit code is an opaque, cryptographically random, single-use code
+handed to an embedded frontend (through a URL fragment) so it can obtain a
+user access token on the core API without a session cookie. The code
+carries no information by itself: everything it references (user, client)
+is stored server-side in the cache, and consumed atomically on exchange.
+"""
+
+import hashlib
+import secrets
+
+from django.conf import settings
+from django.core.cache import cache
+
+
+class TransitCodeService:
+    """Create and consume single-use transit codes."""
+
+    @staticmethod
+    def _cache_key(code):
+        """Build the cache key for a code.
+
+        The code is hashed so that a dump of the cache never reveals
+        directly usable codes.
+        """
+        digest = hashlib.sha256(code.encode("utf-8")).hexdigest()
+        return f"{settings.TRANSIT_CODE_CACHE_PREFIX}:{digest}"
+
+    def create_code(self, user, client_id="unknown"):
+        """Generate a transit code for a user, and store it.
+
+        The code expires after TRANSIT_CODE_TTL seconds.
+
+        Returns:
+            str: The opaque code to hand to the client.
+        """
+        # Default 48 random bytes -> 64 url-safe characters, 384 bits of
+        # entropy: unguessable and safe to transit through a URL fragment.
+        code = secrets.token_urlsafe(settings.TRANSIT_CODE_NBYTES)
+
+        cache.set(
+            self._cache_key(code),
+            {
+                "user_id": str(user.id),
+                "client_id": client_id,
+            },
+            timeout=settings.TRANSIT_CODE_TTL,
+        )
+
+        return code
+
+    def consume_code(self, code):
+        """Consume a transit code, enforcing single use.
+
+        The code is deleted from the cache upon consumption. `cache.delete`
+        returns whether a key was actually deleted, so if two requests race
+        on the same code, only one of them wins.
+
+        Returns:
+            dict | None: The data stored at creation time ('user_id',
+                'client_id'), or None if the code is unknown, expired or
+                already consumed.
+        """
+        if not code:
+            return None
+
+        key = self._cache_key(code)
+        data = cache.get(key)
+
+        if data is None or not cache.delete(key):
+            return None
+
+        return data

src/backend/core/tests/rooms/test_api_rooms_create.py

@@ -2,9 +2,14 @@
 Test rooms API endpoints in the Meet core app: create.
 """
 
+from datetime import datetime, timedelta, timezone
+
+from django.conf import settings as django_settings
+
 # pylint: disable=redefined-outer-name,unused-argument
 from django.core.cache import cache
 
+import jwt
 import pytest
 from rest_framework.test import APIClient
 
@@ -109,3 +114,38 @@ def test_api_rooms_create_authenticated_existing_slug():
 
     assert response.status_code == 400
     assert response.json() == {"slug": ["Room with this Slug already exists."]}
+
+
+def generate_user_access_token(user):
+    """Generate a valid user access JWT signed with the token secret."""
+    now = datetime.now(timezone.utc)
+
+    payload = {
+        "iss": django_settings.USER_ACCESS_TOKEN_ISSUER,
+        "aud": django_settings.USER_ACCESS_TOKEN_AUDIENCE,
+        "iat": now,
+        "exp": now + timedelta(seconds=django_settings.USER_ACCESS_TOKEN_TTL),
+        "user_id": str(user.id),
+        "token_type": "user_access",
+        "client_id": "test-app",
+        "scope": "user:access",
+    }
+
+    return jwt.encode(
+        payload,
+        django_settings.USER_ACCESS_TOKEN_SECRET_KEY,
+        algorithm=django_settings.USER_ACCESS_TOKEN_ALG,
+    )
+
+
+def test_api_rooms_create_authenticated_with_user_access_token():
+    """A user access token should create a room exactly like a session would."""
+    user = UserFactory()
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {generate_user_access_token(user)}")
+    response = client.post("/api/v1.0/rooms/", {"name": "my room"})
+
+    assert response.status_code == 201
+    room = Room.objects.get()
+    assert room.accesses.filter(role="owner", user=user).exists()

src/backend/core/tests/rooms/test_api_rooms_list.py

@@ -2,8 +2,12 @@
 Test rooms API endpoints in the Meet core app: list.
 """
 
+from datetime import datetime, timedelta, timezone
 from unittest import mock
 
+from django.conf import settings as django_settings
+
+import jwt
 import pytest
 from rest_framework.pagination import PageNumberPagination
 from rest_framework.test import APIClient
@@ -156,3 +160,40 @@ def test_api_rooms_list_pagination_page_size():
     assert len(content["results"]) == 3
     assert content["next"] == "http://testserver/api/v1.0/rooms/?page=2&page_size=3"
     assert content["previous"] is None
+
+
+def generate_user_access_token(user):
+    """Generate a valid user access JWT signed with the token secret."""
+    now = datetime.now(timezone.utc)
+
+    payload = {
+        "iss": django_settings.USER_ACCESS_TOKEN_ISSUER,
+        "aud": django_settings.USER_ACCESS_TOKEN_AUDIENCE,
+        "iat": now,
+        "exp": now + timedelta(seconds=django_settings.USER_ACCESS_TOKEN_TTL),
+        "user_id": str(user.id),
+        "token_type": "user_access",
+        "client_id": "test-app",
+        "scope": "user:access",
+    }
+
+    return jwt.encode(
+        payload,
+        django_settings.USER_ACCESS_TOKEN_SECRET_KEY,
+        algorithm=django_settings.USER_ACCESS_TOKEN_ALG,
+    )
+
+
+def test_api_rooms_list_authenticated_with_user_access_token():
+    """A user access token should list rooms exactly like a session would."""
+    user = UserFactory()
+    room = RoomFactory(users=[(user, "owner")])
+    RoomFactory()  # another user's room, not listed
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {generate_user_access_token(user)}")
+    response = client.get("/api/v1.0/rooms/")
+
+    assert response.status_code == 200
+    assert response.data["count"] == 1
+    assert response.data["results"][0]["id"] == str(room.id)

src/backend/core/tests/rooms/test_api_rooms_lobby.py

@@ -14,9 +14,6 @@ from rest_framework.test import APIClient
 from ... import utils
 from ...factories import RoomFactory, UserFactory
 from ...models import RoomAccessLevel
-from ...services.lobby import (
-    LobbyService,
-)
 
 pytestmark = pytest.mark.django_db
 
@@ -29,7 +26,6 @@ def test_request_entry_anonymous(settings):
     room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
     client = APIClient()
 
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.LOBBY_KEY_PREFIX = "mocked-cache-prefix"
 
     # Lobby cache should be empty before the request
@@ -47,11 +43,10 @@ def test_request_entry_anonymous(settings):
 
     assert response.status_code == 200
 
-    # Verify the lobby cookie was properly set
-    cookie = response.cookies.get("mocked-cookie")
-    assert cookie is not None
-
-    participant_id = cookie.value
+    # The participant identifier is returned in the response body; no
+    # cookie is involved anymore
+    assert not response.cookies
+    participant_id = response.json()["id"]
 
     # Verify response content matches expected structure and values
     assert response.json() == {
@@ -78,7 +73,6 @@ def test_request_entry_authenticated_user(settings):
     client = APIClient()
     client.force_login(user)
 
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.LOBBY_KEY_PREFIX = "mocked-cache-prefix"
 
     # Lobby cache should be empty before the request
@@ -96,11 +90,10 @@ def test_request_entry_authenticated_user(settings):
 
     assert response.status_code == 200
 
-    # Verify the lobby cookie was properly set
-    cookie = response.cookies.get("mocked-cookie")
-    assert cookie is not None
-
-    participant_id = cookie.value
+    # The participant identifier is returned in the response body; no
+    # cookie is involved anymore
+    assert not response.cookies
+    participant_id = response.json()["id"]
 
     # Verify response content matches expected structure and values
     assert response.json() == {
@@ -127,7 +120,6 @@ def test_request_entry_with_existing_participants(settings):
     client = APIClient()
 
     # Configure test settings for cookies and cache
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.LOBBY_KEY_PREFIX = "mocked-cache-prefix"
 
     # Add two participants already waiting in the lobby
@@ -168,11 +160,10 @@ def test_request_entry_with_existing_participants(settings):
     # Verify successful response
     assert response.status_code == 200
 
-    # Verify the lobby cookie was properly set for the new participant
-    cookie = response.cookies.get("mocked-cookie")
-    assert cookie is not None
-
-    participant_id = cookie.value
+    # The participant identifier is returned in the response body; no
+    # cookie is involved anymore
+    assert not response.cookies
+    participant_id = response.json()["id"]
 
     # Verify response content matches expected structure and values
     assert response.json() == {
@@ -197,7 +188,6 @@ def test_request_entry_public_room(settings):
     room = RoomFactory(access_level=RoomAccessLevel.PUBLIC)
     client = APIClient()
 
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.LOBBY_KEY_PREFIX = "mocked-cache-prefix"
 
     # Lobby cache should be empty before the request
@@ -206,9 +196,7 @@ def test_request_entry_public_room(settings):
 
     with (
         mock.patch.object(utils, "notify_participants", return_value=None),
-        mock.patch.object(
-            LobbyService, "_get_or_create_participant_id", return_value="123"
-        ),
+        mock.patch("core.services.lobby.uuid.uuid4", return_value="123"),
         mock.patch.object(
             utils, "generate_livekit_config", return_value={"token": "test-token"}
         ),
@@ -221,11 +209,6 @@ def test_request_entry_public_room(settings):
 
     assert response.status_code == 200
 
-    # Verify the lobby cookie was set
-    cookie = response.cookies.get("mocked-cookie")
-    assert cookie is not None
-    assert cookie.value == "123"
-
     # Verify response content matches expected structure and values
     assert response.json() == {
         "id": "123",
@@ -235,9 +218,10 @@ def test_request_entry_public_room(settings):
         "livekit": {"token": "test-token"},
     }
 
-    # Verify lobby cache is still empty after the request
+    # The accepted participant is persisted, out of the waiting list
     lobby_keys = cache.keys(f"mocked-cache-prefix_{room.id}_*")
-    assert not lobby_keys
+    assert len(lobby_keys) == 1
+    assert cache.get(lobby_keys[0])["status"] == "accepted"
 
 
 def test_request_entry_authenticated_user_public_room(settings):
@@ -247,7 +231,6 @@ def test_request_entry_authenticated_user_public_room(settings):
     client = APIClient()
     client.force_login(user)
 
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.LOBBY_KEY_PREFIX = "mocked-cache-prefix"
 
     # Lobby cache should be empty before the request
@@ -256,9 +239,8 @@ def test_request_entry_authenticated_user_public_room(settings):
 
     with (
         mock.patch.object(utils, "notify_participants", return_value=None),
-        mock.patch.object(
-            LobbyService,
-            "_get_or_create_participant_id",
+        mock.patch(
+            "core.services.lobby.uuid.uuid4",
             return_value="2f7f162f-e7d1-421b-90e7-02bfbfbf8def",
         ),
         mock.patch.object(
@@ -273,11 +255,6 @@ def test_request_entry_authenticated_user_public_room(settings):
 
     assert response.status_code == 200
 
-    # Verify the lobby cookie was set
-    cookie = response.cookies.get("mocked-cookie")
-    assert cookie is not None
-    assert cookie.value == "2f7f162f-e7d1-421b-90e7-02bfbfbf8def"
-
     # Verify response content matches expected structure and values
     assert response.json() == {
         "id": "2f7f162f-e7d1-421b-90e7-02bfbfbf8def",
@@ -287,9 +264,10 @@ def test_request_entry_authenticated_user_public_room(settings):
         "livekit": {"token": "test-token"},
     }
 
-    # Verify lobby cache is still empty after the request
+    # The accepted participant is persisted, out of the waiting list
     lobby_keys = cache.keys(f"mocked-cache-prefix_{room.id}_*")
-    assert not lobby_keys
+    assert len(lobby_keys) == 1
+    assert cache.get(lobby_keys[0])["status"] == "accepted"
 
 
 def test_request_entry_waiting_participant_public_room(settings):
@@ -297,7 +275,6 @@ def test_request_entry_waiting_participant_public_room(settings):
     room = RoomFactory(access_level=RoomAccessLevel.PUBLIC)
     client = APIClient()
 
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.LOBBY_KEY_PREFIX = "mocked-cache-prefix"
 
     # Add a waiting participant to the room's lobby cache
@@ -311,9 +288,7 @@ def test_request_entry_waiting_participant_public_room(settings):
         },
     )
 
-    # Simulate a browser with existing participant cookie
-    client.cookies.load({"mocked-cookie": "2f7f162f-e7d1-421b-90e7-02bfbfbf8def"})
-
+    # Simulate a returning participant echoing its identifier
     with (
         mock.patch.object(utils, "notify_participants", return_value=None),
         mock.patch.object(
@@ -322,16 +297,14 @@ def test_request_entry_waiting_participant_public_room(settings):
     ):
         response = client.post(
             f"/api/v1.0/rooms/{room.id}/request-entry/",
-            {"username": "user1"},
+            {
+                "username": "user1",
+                "participant_id": "2f7f162f-e7d1-421b-90e7-02bfbfbf8def",
+            },
         )
 
     assert response.status_code == 200
 
-    # Verify the lobby cookie was set
-    cookie = response.cookies.get("mocked-cookie")
-    assert cookie is not None
-    assert cookie.value == "2f7f162f-e7d1-421b-90e7-02bfbfbf8def"
-
     # Verify response content matches expected structure and values
     assert response.json() == {
         "id": "2f7f162f-e7d1-421b-90e7-02bfbfbf8def",
@@ -637,15 +610,14 @@ def test_list_waiting_participants_empty(settings):
 @mock.patch.object(
     utils, "generate_livekit_config", return_value={"token": "test-token"}
 )
-def test_request_entry_throttling_anonymous_without_cookie(
+def test_request_entry_throttling_anonymous_unidentified(
     mock_notify_participants, mock_generate_livekit_config, settings
 ):
-    """Anonymous users without a cookie should not be throttled."""
+    """Requests without a participant identifier should not be throttled."""
 
     room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
     client = APIClient()
 
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.REST_FRAMEWORK["DEFAULT_THROTTLE_RATES"]["request_entry"] = "1/minute"
 
     response = client.post(
@@ -654,9 +626,6 @@ def test_request_entry_throttling_anonymous_without_cookie(
     )
 
     assert response.status_code == 200
-    assert response.cookies.get("mocked-cookie") is not None
-
-    client.cookies.clear()  # Simulate a new cookieless request
 
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/request-entry/",
@@ -670,34 +639,32 @@ def test_request_entry_throttling_anonymous_without_cookie(
 @mock.patch.object(
     utils, "generate_livekit_config", return_value={"token": "test-token"}
 )
-def test_request_entry_throttling_anonymous_with_cookie(
+def test_request_entry_throttling_anonymous_identified(
     mock_notify_participants, mock_generate_livekit_config, settings
 ):
-    """Anonymous users with a cookie should be throttled after exceeding the rate limit."""
+    """Identified requests should be throttled after exceeding the rate limit."""
     room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
     client = APIClient()
 
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.REST_FRAMEWORK["DEFAULT_THROTTLE_RATES"]["request_entry"] = "2/minute"
 
     participant_id = str(uuid.uuid4())
-    client.cookies.load({"mocked-cookie": participant_id})
 
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/request-entry/",
-        {"username": "test_user"},
+        {"username": "test_user", "participant_id": participant_id},
     )
     assert response.status_code == 200
 
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/request-entry/",
-        {"username": "test_user"},
+        {"username": "test_user", "participant_id": participant_id},
     )
     assert response.status_code == 200
 
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/request-entry/",
-        {"username": "test_user"},
+        {"username": "test_user", "participant_id": participant_id},
     )
 
     assert response.status_code == 429
@@ -716,7 +683,6 @@ def test_request_entry_throttling_authenticated_user(
     client = APIClient()
     client.force_login(user)
 
-    settings.LOBBY_COOKIE_NAME = "mocked-cookie"
     settings.REST_FRAMEWORK["DEFAULT_THROTTLE_RATES"]["request_entry"] = "2/minute"
 
     response = client.post(
@@ -737,3 +703,124 @@ def test_request_entry_throttling_authenticated_user(
     )
 
     assert response.status_code == 429
+
+
+def test_request_entry_with_participant_id(settings):
+    """Echoing the previously issued identifier preserves the lobby identity across requests."""
+    room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
+    client = APIClient()
+
+    settings.LOBBY_KEY_PREFIX = "mocked-cache-prefix"
+
+    with (
+        mock.patch.object(utils, "notify_participants", return_value=None),
+        mock.patch.object(utils, "generate_color", return_value="mocked-color"),
+    ):
+        response = client.post(
+            f"/api/v1.0/rooms/{room.id}/request-entry/",
+            {"username": "test_user"},
+        )
+
+        assert response.status_code == 200
+        participant_id = response.json()["id"]
+
+        # Echoing the identifier must be recognized as the same
+        # participant: no duplicate in the lobby
+        response = client.post(
+            f"/api/v1.0/rooms/{room.id}/request-entry/",
+            {"username": "test_user", "participant_id": participant_id},
+        )
+
+    assert response.status_code == 200
+    assert response.json()["id"] == participant_id
+    assert response.json()["status"] == "waiting"
+
+    lobby_keys = cache.keys(f"mocked-cache-prefix_{room.id}_*")
+    assert len(lobby_keys) == 1
+
+
+def test_request_entry_unknown_participant_id_not_seeded(settings):
+    """An identifier unknown to the room's lobby must not be honored."""
+    room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
+    client = APIClient()
+
+    settings.LOBBY_KEY_PREFIX = "mocked-cache-prefix"
+
+    forged_id = str(uuid.uuid4())
+
+    with (
+        mock.patch.object(utils, "notify_participants", return_value=None),
+        mock.patch.object(utils, "generate_color", return_value="mocked-color"),
+    ):
+        response = client.post(
+            f"/api/v1.0/rooms/{room.id}/request-entry/",
+            {"username": "test_user", "participant_id": forged_id},
+        )
+
+    assert response.status_code == 200
+    assert response.json()["id"] != forged_id
+
+    # Nothing was stored under the forged identifier
+    assert cache.get(f"mocked-cache-prefix_{room.id}_{forged_id}") is None
+
+
+def test_request_entry_participant_id_bound_to_room(settings):
+    """An identifier minted for one room must not be honored in another."""
+    room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
+    other_room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
+    client = APIClient()
+
+    with (
+        mock.patch.object(utils, "notify_participants", return_value=None),
+        mock.patch.object(utils, "generate_color", return_value="mocked-color"),
+    ):
+        response = client.post(
+            f"/api/v1.0/rooms/{room.id}/request-entry/",
+            {"username": "test_user"},
+        )
+        participant_id = response.json()["id"]
+
+        response = client.post(
+            f"/api/v1.0/rooms/{other_room.id}/request-entry/",
+            {"username": "test_user", "participant_id": participant_id},
+        )
+
+    assert response.status_code == 200
+    assert response.json()["id"] != participant_id
+
+
+def test_request_entry_legacy_cookie_ignored():
+    """The retired cookie channel must not be honored anymore."""
+    room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
+    client = APIClient()
+
+    legacy_participant_id = str(uuid.uuid4())
+    client.cookies["lobbyParticipantId"] = legacy_participant_id
+
+    with (
+        mock.patch.object(utils, "notify_participants", return_value=None),
+        mock.patch.object(utils, "generate_color", return_value="mocked-color"),
+    ):
+        response = client.post(
+            f"/api/v1.0/rooms/{room.id}/request-entry/",
+            {"username": "test_user"},
+        )
+
+    assert response.status_code == 200
+    returned_id = response.json()["id"]
+    assert returned_id != legacy_participant_id
+    uuid.UUID(returned_id)
+
+
+def test_request_entry_malformed_participant_id(settings):
+    """A non-UUID identifier is rejected by the serializer with a 400."""
+    room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
+    client = APIClient()
+
+    response = client.post(
+        f"/api/v1.0/rooms/{room.id}/request-entry/",
+        {"username": "test_user", "participant_id": "../../../evil-key"},
+    )
+
+    assert response.status_code == 400
+    assert "participant_id" in response.json()

src/backend/core/tests/rooms/test_api_rooms_participants_management.py

@@ -20,7 +20,11 @@ from rest_framework.test import APIClient
 
 from core import utils
 from core.factories import RoomFactory, UserFactory, UserResourceAccessFactory
-from core.services.lobby import LobbyService
+from core.services.lobby import (
+    LobbyParticipant,
+    LobbyParticipantStatus,
+    LobbyService,
+)
 
 pytestmark = pytest.mark.django_db
 
@@ -87,7 +91,7 @@ def test_mute_participant_with_livekit_token_for_this_room(mock_livekit_client):
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -113,7 +117,7 @@ def test_mute_participant_with_livekit_token_for_another_room_forbidden(
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -153,7 +157,7 @@ def test_mute_participant_everyone_can_mute_disabled_blocks_non_admin(
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -300,7 +304,7 @@ def test_mute_participant_admin_with_token_for_this_room(mock_livekit_client):
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -330,7 +334,7 @@ def test_mute_participant_admin_with_token_for_another_room(mock_livekit_client)
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -361,7 +365,7 @@ def test_mute_participant_admin_token_replayed_does_not_grant_admin(
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -381,7 +385,7 @@ def test_mute_participant_livekit_token_triggers_presence_check(mock_livekit_cli
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -412,7 +416,7 @@ def test_mute_participant_livekit_token_presence_check_returns_participant(
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -440,7 +444,7 @@ def test_mute_participant_livekit_token_presence_check_participant_not_found(
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -469,7 +473,7 @@ def test_mute_participant_livekit_token_presence_check_twirp_error_forbidden(
         url,
         {"participant_identity": str(uuid4()), "track_sid": "test-track-sid"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -849,7 +853,15 @@ def test_remove_participant_success_lobby_cache(mock_livekit_client):
     participant_identity = str(uuid4())
 
     # Create participant in lobby cache first
-    LobbyService().enter(room.id, participant_identity, "John doe")
+    LobbyService()._save_participant(
+        room.id,
+        LobbyParticipant(
+            id=participant_identity,
+            username="John doe",
+            status=LobbyParticipantStatus.WAITING,
+            color="#123456",
+        ),
+    )
 
     # Accept participant
     LobbyService().handle_participant_entry(room.id, participant_identity, True)
@@ -1020,3 +1032,6 @@ def test_remove_participant_not_found(mock_livekit_client):
     assert response.data == {"error": "Participant not found"}
 
     mock_livekit_client.aclose.assert_called_once()
+
+
+# todo - try to pass another scheme to make sure it defers to the next auth

src/backend/core/tests/rooms/test_api_rooms_rename_toggle.py

@@ -69,7 +69,10 @@ def test_toggle_hand_raise_success(mock_livekit_client, room, token):
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": room.id})
     response = client.post(
-        url, {"raised": True}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"raised": True},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-token {token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -84,7 +87,10 @@ def test_toggle_hand_lower_success(mock_livekit_client, room, token):
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": room.id})
     response = client.post(
-        url, {"raised": False}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"raised": False},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -101,7 +107,10 @@ def test_toggle_hand_raise_sets_timestamp(mock_livekit_client, room, token):
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": room.id})
     response = client.post(
-        url, {"raised": True}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"raised": True},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -117,7 +126,10 @@ def test_toggle_hand_identity_derived_from_token(
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": room.id})
     client.post(
-        url, {"raised": True}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"raised": True},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     call_kwargs = mock_livekit_client.room.update_participant.call_args
@@ -128,7 +140,9 @@ def test_toggle_hand_missing_raised_field(room, token):
     """Test toggle hand with missing raised field returns 400."""
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": room.id})
-    response = client.post(url, {}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}")
+    response = client.post(
+        url, {}, format="json", HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}"
+    )
 
     assert response.status_code == status.HTTP_400_BAD_REQUEST
     assert "raised" in response.data
@@ -142,7 +156,7 @@ def test_toggle_hand_invalid_raised_field(room, token):
         url,
         {"raised": "not-a-boolean"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_400_BAD_REQUEST
@@ -166,7 +180,10 @@ def test_toggle_hand_forbidden_token_for_wrong_room(user):
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": target_room.id})
     response = client.post(
-        url, {"raised": True}, format="json", HTTP_AUTHORIZATION=f"Bearer {wrong_token}"
+        url,
+        {"raised": True},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {wrong_token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -181,7 +198,10 @@ def test_toggle_hand_unexpected_twirp_error(mock_livekit_client, room, token):
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": room.id})
     response = client.post(
-        url, {"raised": True}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"raised": True},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_500_INTERNAL_SERVER_ERROR
@@ -200,7 +220,7 @@ def test_toggle_hand_raise_success_anonymous(
         url,
         {"raised": True},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {anonymous_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {anonymous_token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -220,7 +240,7 @@ def test_toggle_hand_lower_success_anonymous(
         url,
         {"raised": False},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {anonymous_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {anonymous_token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -240,7 +260,7 @@ def test_toggle_hand_identity_derived_from_token_anonymous(
         url,
         {"raised": True},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {anonymous_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {anonymous_token}",
     )
 
     call_kwargs = mock_livekit_client.room.update_participant.call_args
@@ -257,7 +277,10 @@ def test_rename_participant_success(mock_livekit_client, room, token):
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": room.id})
     response = client.post(
-        url, {"name": "John Doe"}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"name": "John Doe"},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -272,7 +295,10 @@ def test_rename_participant_sets_correct_name(mock_livekit_client, room, token):
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": room.id})
     client.post(
-        url, {"name": "Jane Doe"}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"name": "Jane Doe"},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     call_kwargs = mock_livekit_client.room.update_participant.call_args
@@ -286,7 +312,10 @@ def test_rename_participant_uses_identity_from_token(
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": room.id})
     client.post(
-        url, {"name": "John Doe"}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"name": "John Doe"},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     call_kwargs = mock_livekit_client.room.update_participant.call_args
@@ -298,7 +327,7 @@ def test_rename_participant_empty_name(room, token):
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": room.id})
     response = client.post(
-        url, {"name": ""}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url, {"name": ""}, format="json", HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}"
     )
 
     assert response.status_code == status.HTTP_400_BAD_REQUEST
@@ -309,7 +338,9 @@ def test_rename_participant_missing_name(room, token):
     """Test rename with missing name field returns 400."""
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": room.id})
-    response = client.post(url, {}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}")
+    response = client.post(
+        url, {}, format="json", HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}"
+    )
 
     assert response.status_code == status.HTTP_400_BAD_REQUEST
     assert "name" in response.data
@@ -320,7 +351,10 @@ def test_rename_participant_name_too_long(room, token):
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": room.id})
     response = client.post(
-        url, {"name": "a" * 256}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"name": "a" * 256},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_400_BAD_REQUEST
@@ -348,7 +382,7 @@ def test_rename_participant_forbidden_token_for_wrong_room(user):
         url,
         {"name": "John Doe"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {wrong_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {wrong_token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -363,7 +397,10 @@ def test_rename_participant_unexpected_twirp_error(mock_livekit_client, room, to
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": room.id})
     response = client.post(
-        url, {"name": "John Doe"}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"name": "John Doe"},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_500_INTERNAL_SERVER_ERROR
@@ -382,7 +419,7 @@ def test_rename_participant_success_anonymous(
         url,
         {"name": "Guest User"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {anonymous_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {anonymous_token}",
     )
 
     assert response.status_code == status.HTTP_200_OK
@@ -402,7 +439,7 @@ def test_rename_participant_uses_identity_from_token_anonymous(
         url,
         {"name": "Guest User"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {anonymous_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {anonymous_token}",
     )
 
     call_kwargs = mock_livekit_client.room.update_participant.call_args
@@ -419,7 +456,7 @@ def test_rename_participant_sets_correct_name_anonymous(
         url,
         {"name": "Guest User"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {anonymous_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {anonymous_token}",
     )
 
     call_kwargs = mock_livekit_client.room.update_participant.call_args
@@ -436,7 +473,7 @@ def test_rename_participant_forbidden_anonymous_token_for_wrong_room(anonymous_t
         url,
         {"name": "Guest User"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {anonymous_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {anonymous_token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -462,7 +499,7 @@ def test_toggle_hand_expired_token(room, expired_token):
         url,
         {"raised": True},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {expired_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {expired_token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -476,7 +513,7 @@ def test_rename_participant_expired_token(room, expired_token):
         url,
         {"name": "John Doe"},
         format="json",
-        HTTP_AUTHORIZATION=f"Bearer {expired_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {expired_token}",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -490,7 +527,7 @@ def test_toggle_hand_malformed_token(room):
         url,
         {"raised": True},
         format="json",
-        HTTP_AUTHORIZATION="Bearer this-is-not-a-valid-jwt",
+        HTTP_AUTHORIZATION="X-LiveKit-Token this-is-not-a-valid-jwt",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -504,7 +541,10 @@ def test_toggle_hand_room_not_found(user):
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": non_existent_room_id})
     response = client.post(
-        url, {"raised": True}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"raised": True},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_404_NOT_FOUND
@@ -519,7 +559,10 @@ def test_toggle_hand_participant_not_found(mock_livekit_client, room, token):
     client = APIClient()
     url = reverse("rooms-toggle-hand", kwargs={"pk": room.id})
     response = client.post(
-        url, {"raised": True}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"raised": True},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_404_NOT_FOUND
@@ -536,7 +579,7 @@ def test_rename_participant_malformed_token(room):
         url,
         {"name": "John Doe"},
         format="json",
-        HTTP_AUTHORIZATION="Bearer this-is-not-a-valid-jwt",
+        HTTP_AUTHORIZATION="X-LiveKit-Token this-is-not-a-valid-jwt",
     )
 
     assert response.status_code == status.HTTP_403_FORBIDDEN
@@ -550,7 +593,10 @@ def test_rename_participant_room_not_found(user):
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": non_existent_room_id})
     response = client.post(
-        url, {"name": "John Doe"}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"name": "John Doe"},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_404_NOT_FOUND
@@ -565,10 +611,16 @@ def test_rename_participant_not_found(mock_livekit_client, room, token):
     client = APIClient()
     url = reverse("rooms-rename", kwargs={"pk": room.id})
     response = client.post(
-        url, {"name": "John Doe"}, format="json", HTTP_AUTHORIZATION=f"Bearer {token}"
+        url,
+        {"name": "John Doe"},
+        format="json",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {token}",
     )
 
     assert response.status_code == status.HTTP_404_NOT_FOUND
     assert response.data == {"error": "Participant not found"}
 
     mock_livekit_client.aclose.assert_called_once()
+
+
+# todo - try to pass another scheme to make sure it defers to the next auth

src/backend/core/tests/rooms/test_api_rooms_retrieve.py

@@ -3,11 +3,14 @@ Test rooms API endpoints in the Meet core app: retrieve.
 """
 
 import random
+from datetime import datetime, timedelta, timezone
 from unittest import mock
 
+from django.conf import settings as django_settings
 from django.contrib.auth.models import AnonymousUser
 from django.test.utils import override_settings
 
+import jwt
 import pytest
 from rest_framework.test import APIClient
 
@@ -503,3 +506,40 @@ def test_api_rooms_retrieve_administrators(
         role=str(user_access.role),
         participant_id=None,
     )
+
+
+def generate_user_access_token(user):
+    """Generate a valid user access JWT signed with the token secret."""
+    now = datetime.now(timezone.utc)
+
+    payload = {
+        "iss": django_settings.USER_ACCESS_TOKEN_ISSUER,
+        "aud": django_settings.USER_ACCESS_TOKEN_AUDIENCE,
+        "iat": now,
+        "exp": now + timedelta(seconds=django_settings.USER_ACCESS_TOKEN_TTL),
+        "user_id": str(user.id),
+        "token_type": "user_access",
+        "client_id": "test-app",
+        "scope": "user:access",
+    }
+
+    return jwt.encode(
+        payload,
+        django_settings.USER_ACCESS_TOKEN_SECRET_KEY,
+        algorithm=django_settings.USER_ACCESS_TOKEN_ALG,
+    )
+
+
+def test_api_rooms_retrieve_authenticated_with_user_access_token():
+    """A user access token should retrieve a room exactly like a session would."""
+    user = UserFactory()
+    room = RoomFactory(users=[(user, "owner")])
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {generate_user_access_token(user)}")
+    response = client.get(f"/api/v1.0/rooms/{room.id!s}/")
+
+    assert response.status_code == 200
+    assert response.data["id"] == str(room.id)
+    # Authenticated as the owner: privileged fields are included
+    assert response.data["pin_code"] == room.pin_code

src/backend/core/tests/rooms/test_api_rooms_subtitle.py

@@ -110,7 +110,7 @@ def test_start_subtitle_invalid_token():
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/start-subtitle/",
         {},
-        HTTP_AUTHORIZATION="Bearer invalid-token",
+        HTTP_AUTHORIZATION="X-LiveKit-Token invalid-token",
     )
 
     assert response.status_code == 403
@@ -128,7 +128,7 @@ def test_start_subtitle_disabled_by_default(mock_livekit_token):
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/start-subtitle/",
         {},
-        HTTP_AUTHORIZATION=f"Bearer {mock_livekit_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {mock_livekit_token}",
     )
 
     assert response.status_code == 404
@@ -148,7 +148,7 @@ def test_start_subtitle_valid_token(
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/start-subtitle/",
         {},
-        HTTP_AUTHORIZATION=f"Bearer {mock_livekit_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {mock_livekit_token}",
     )
 
     assert response.status_code == 200
@@ -178,7 +178,7 @@ def test_start_subtitle_twirp_error(
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/start-subtitle/",
         {},
-        HTTP_AUTHORIZATION=f"Bearer {mock_livekit_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {mock_livekit_token}",
     )
 
     assert response.status_code == 500
@@ -198,7 +198,7 @@ def test_start_subtitle_wrong_room(settings, mock_livekit_token):
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/start-subtitle/",
         {},
-        HTTP_AUTHORIZATION=f"Bearer {mock_livekit_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {mock_livekit_token}",
     )
 
     assert response.status_code == 403
@@ -219,10 +219,13 @@ def test_start_subtitle_wrong_signature(settings, mock_livekit_token):
     response = client.post(
         f"/api/v1.0/rooms/{room.id}/start-subtitle/",
         {},
-        HTTP_AUTHORIZATION=f"Bearer {mock_livekit_token}",
+        HTTP_AUTHORIZATION=f"X-LiveKit-Token {mock_livekit_token}",
     )
 
     assert response.status_code == 403
     assert response.json() == {
         "detail": "Invalid LiveKit token: Signature verification failed"
     }
+
+
+# todo - try to pass another scheme to make sure it defers to the next auth

src/backend/core/tests/rooms/test_api_rooms_update.py

@@ -3,8 +3,12 @@ Test rooms API endpoints in the Meet core app: update.
 """
 
 import random
+from datetime import datetime, timedelta, timezone
 from unittest.mock import patch
 
+from django.conf import settings as django_settings
+
+import jwt
 import pytest
 from rest_framework.test import APIClient
 
@@ -437,3 +441,45 @@ def test_api_rooms_update_livekit_sync_failure(mock_update_metadata):
             "configuration": {"can_publish_sources": ["camera"]},
         },
     )
+
+
+def generate_user_access_token(user):
+    """Generate a valid user access JWT signed with the token secret."""
+    now = datetime.now(timezone.utc)
+
+    payload = {
+        "iss": django_settings.USER_ACCESS_TOKEN_ISSUER,
+        "aud": django_settings.USER_ACCESS_TOKEN_AUDIENCE,
+        "iat": now,
+        "exp": now + timedelta(seconds=django_settings.USER_ACCESS_TOKEN_TTL),
+        "user_id": str(user.id),
+        "token_type": "user_access",
+        "client_id": "test-app",
+        "scope": "user:access",
+    }
+
+    return jwt.encode(
+        payload,
+        django_settings.USER_ACCESS_TOKEN_SECRET_KEY,
+        algorithm=django_settings.USER_ACCESS_TOKEN_ALG,
+    )
+
+
+def test_api_rooms_update_authenticated_with_user_access_token():
+    """Role-based permissions apply unchanged with a user access token."""
+    user = UserFactory()
+    room = RoomFactory(users=[(user, "member")])
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {generate_user_access_token(user)}")
+
+    # A simple member cannot update the room
+    response = client.patch(f"/api/v1.0/rooms/{room.id!s}/", {"name": "new name"})
+    assert response.status_code == 403
+
+    # An administrator can
+    room.accesses.filter(user=user).update(role="administrator")
+    response = client.patch(f"/api/v1.0/rooms/{room.id!s}/", {"name": "new name"})
+    assert response.status_code == 200
+    room.refresh_from_db()
+    assert room.name == "new name"

src/backend/core/tests/services/test_lobby.py

@@ -3,7 +3,6 @@ Test lobby service.
 """
 
 # pylint: disable=W0621,W0613, W0212, R0913
-# ruff: noqa: PLR0913
 
 import uuid
 from unittest import mock
@@ -11,7 +10,6 @@ from unittest import mock
 from django.conf import settings
 from django.contrib.auth.models import AnonymousUser
 from django.core.cache import cache
-from django.http import HttpResponse
 
 import pytest
 
@@ -135,59 +133,6 @@ def test_get_cache_key(lobby_service, participant_id):
     assert cache_key == expected_key
 
 
-def test_get_or_create_participant_id_from_cookie(lobby_service):
-    """Test extracting participant ID from cookie."""
-    request = mock.Mock()
-    request.COOKIES = {settings.LOBBY_COOKIE_NAME: "existing-id"}
-
-    participant_id = lobby_service._get_or_create_participant_id(request)
-
-    assert participant_id == "existing-id"
-
-
-@mock.patch.object(uuid, "uuid4", return_value="generated-id")
-def test_get_or_create_participant_id_new(mock_uuid4, lobby_service):
-    """Test creating new participant ID when cookie is missing."""
-    request = mock.Mock()
-    request.COOKIES = {}
-
-    participant_id = lobby_service._get_or_create_participant_id(request)
-
-    assert participant_id == "generated-id"
-    mock_uuid4.assert_called_once()
-
-
-def test_prepare_response_existing_cookie(lobby_service, participant_id):
-    """Test response preparation with existing cookie."""
-    response = HttpResponse()
-    response.cookies[settings.LOBBY_COOKIE_NAME] = "existing-cookie"
-
-    lobby_service.prepare_response(response, participant_id)
-
-    # Verify cookie wasn't set again
-    cookie = response.cookies.get(settings.LOBBY_COOKIE_NAME)
-    assert cookie.value == "existing-cookie"
-    assert cookie.value != participant_id
-
-
-def test_prepare_response_new_cookie(lobby_service, participant_id):
-    """Test response preparation with new cookie."""
-    response = HttpResponse()
-
-    lobby_service.prepare_response(response, participant_id)
-
-    # Verify cookie was set
-    cookie = response.cookies.get(settings.LOBBY_COOKIE_NAME)
-    assert cookie is not None
-    assert cookie.value == participant_id
-    assert cookie["httponly"] is True
-    assert cookie["secure"] is True
-    assert cookie["samesite"] == "Lax"
-
-    # It's a session cookies (no max_age specified):
-    assert not cookie["max-age"]
-
-
 def test_can_bypass_lobby_public_room(lobby_service):
     """Should return True for public rooms regardless of user auth and role."""
     room = RoomFactory(access_level=RoomAccessLevel.PUBLIC)
@@ -266,11 +211,12 @@ def test_request_entry_public_room(
         color="#123456",
     )
 
-    lobby_service._get_or_create_participant_id = mock.Mock(return_value=participant_id)
     lobby_service._get_participant = mock.Mock(return_value=mocked_participant)
     mock_generate_config.return_value = {"token": "test-token"}
 
-    participant, livekit_config = lobby_service.request_entry(room, request, username)
+    participant, livekit_config = lobby_service.request_entry(
+        room, request, username, participant_id=participant_id
+    )
 
     assert participant.status == LobbyParticipantStatus.ACCEPTED
     assert livekit_config == {"token": "test-token"}
@@ -304,11 +250,12 @@ def test_request_entry_trusted_room(
         color="#123456",
     )
 
-    lobby_service._get_or_create_participant_id = mock.Mock(return_value=participant_id)
     lobby_service._get_participant = mock.Mock(return_value=mocked_participant)
     mock_generate_config.return_value = {"token": "test-token"}
 
-    participant, livekit_config = lobby_service.request_entry(room, request, username)
+    participant, livekit_config = lobby_service.request_entry(
+        room, request, username, participant_id=participant_id
+    )
 
     assert participant.status == LobbyParticipantStatus.ACCEPTED
     assert livekit_config == {"token": "test-token"}
@@ -325,18 +272,19 @@ def test_request_entry_trusted_room(
     lobby_service._get_participant.assert_called_once_with(room.id, participant_id)
 
 
-@mock.patch("core.services.lobby.LobbyService.enter")
+@mock.patch("core.services.lobby.LobbyService._notify_entry_request")
+@mock.patch("core.services.lobby.LobbyService._create_participant")
 def test_request_entry_new_participant(
-    mock_enter, lobby_service, participant_id, username
+    mock_create, mock_notify, lobby_service, participant_id, username
 ):
-    """Test requesting entry for a new participant."""
+    """A new participant gets a server-minted identifier - any provided
+    one is unknown to the lobby and therefore discarded - and the room is
+    notified of the entry request."""
     request = mock.Mock()
-    request.COOKIES = {settings.LOBBY_COOKIE_NAME: participant_id}
     request.user = AnonymousUser()
 
     room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
 
-    lobby_service._get_or_create_participant_id = mock.Mock(return_value=participant_id)
     lobby_service._get_participant = mock.Mock(return_value=None)
 
     participant_data = LobbyParticipant(
@@ -345,14 +293,20 @@ def test_request_entry_new_participant(
         id=participant_id,
         color="#123456",
     )
-    mock_enter.return_value = participant_data
+    mock_create.return_value = participant_data
 
-    participant, livekit_config = lobby_service.request_entry(room, request, username)
+    forged_id = str(uuid.uuid4())
+    participant, livekit_config = lobby_service.request_entry(
+        room, request, username, participant_id=forged_id
+    )
 
     assert participant == participant_data
     assert livekit_config is None
-    mock_enter.assert_called_once_with(room.id, participant_id, username)
-    lobby_service._get_participant.assert_called_once_with(room.id, participant_id)
+    # The provided identifier was looked up, found unknown, and replaced
+    # by a freshly minted participant
+    lobby_service._get_participant.assert_called_once_with(room.id, forged_id)
+    mock_create.assert_called_once_with(room.id, username)
+    mock_notify.assert_called_once_with(str(room.id))
 
 
 @mock.patch("core.services.lobby.LobbyService.refresh_waiting_status")
@@ -361,7 +315,6 @@ def test_request_entry_waiting_participant(
 ):
     """Test requesting entry for a waiting participant."""
     request = mock.Mock()
-    request.COOKIES = {settings.LOBBY_COOKIE_NAME: participant_id}
     request.user = AnonymousUser()
 
     room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
@@ -372,10 +325,11 @@ def test_request_entry_waiting_participant(
         id=participant_id,
         color="#123456",
     )
-    lobby_service._get_or_create_participant_id = mock.Mock(return_value=participant_id)
     lobby_service._get_participant = mock.Mock(return_value=mocked_participant)
 
-    participant, livekit_config = lobby_service.request_entry(room, request, username)
+    participant, livekit_config = lobby_service.request_entry(
+        room, request, username, participant_id=participant_id
+    )
 
     assert participant.status == LobbyParticipantStatus.WAITING
     assert livekit_config is None
@@ -390,7 +344,6 @@ def test_request_entry_accepted_participant(
     """Test requesting entry for an accepted participant."""
     request = mock.Mock()
     request.user = AnonymousUser()
-    request.COOKIES = {settings.LOBBY_COOKIE_NAME: participant_id}
 
     room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
 
@@ -400,12 +353,13 @@ def test_request_entry_accepted_participant(
         id=participant_id,
         color="#123456",
     )
-    lobby_service._get_or_create_participant_id = mock.Mock(return_value=participant_id)
     lobby_service._get_participant = mock.Mock(return_value=mocked_participant)
 
     mock_generate_config.return_value = {"token": "test-token"}
 
-    participant, livekit_config = lobby_service.request_entry(room, request, username)
+    participant, livekit_config = lobby_service.request_entry(
+        room, request, username, participant_id=participant_id
+    )
 
     assert participant.status == LobbyParticipantStatus.ACCEPTED
     assert livekit_config == {"token": "test-token"}
@@ -428,7 +382,6 @@ def test_request_entry_participant_with_role(
     """Test requesting entry for a participant with a role on the room."""
     request = mock.Mock()
     request.user = UserFactory()
-    request.COOKIES = {settings.LOBBY_COOKIE_NAME: participant_id}
 
     room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
 
@@ -440,12 +393,13 @@ def test_request_entry_participant_with_role(
         id=participant_id,
         color="#123456",
     )
-    lobby_service._get_or_create_participant_id = mock.Mock(return_value=participant_id)
     lobby_service._get_participant = mock.Mock(return_value=mocked_participant)
 
     mock_generate_config.return_value = {"token": "test-token"}
 
-    participant, livekit_config = lobby_service.request_entry(room, request, username)
+    participant, livekit_config = lobby_service.request_entry(
+        room, request, username, participant_id=participant_id
+    )
 
     assert participant.status == LobbyParticipantStatus.ACCEPTED
     assert livekit_config == {"token": "test-token"}
@@ -472,73 +426,47 @@ def test_refresh_waiting_status(mock_cache, lobby_service, participant_id):
     )
 
 
-# pylint: disable=R0917
 @mock.patch("core.services.lobby.cache")
 @mock.patch("core.utils.generate_color")
-@mock.patch("core.utils.notify_participants")
-def test_enter_success(
-    mock_notify,
+def test_create_participant(
     mock_generate_color,
     mock_cache,
     lobby_service,
-    participant_id,
     username,
+    settings,
 ):
-    """Test successful participant entry."""
+    """A created participant is waiting, colored, and persisted."""
     mock_generate_color.return_value = "#123456"
     lobby_service._get_cache_key = mock.Mock(return_value="mocked_cache_key")
 
     room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
-    participant = lobby_service.enter(room.id, participant_id, username)
+    participant = lobby_service._create_participant(room.id, username)
 
-    mock_generate_color.assert_called_once_with(participant_id)
+    # The identifier is minted server-side
+    uuid.UUID(participant.id)
+    mock_generate_color.assert_called_once_with(participant.id)
     assert participant.status == LobbyParticipantStatus.WAITING
     assert participant.username == username
-    assert participant.id == participant_id
     assert participant.color == "#123456"
 
-    lobby_service._get_cache_key.assert_called_once_with(room.id, participant_id)
+    lobby_service._get_cache_key.assert_called_once_with(room.id, participant.id)
 
     mock_cache.set.assert_called_once_with(
         "mocked_cache_key",
         participant.to_dict(),
         timeout=settings.LOBBY_WAITING_TIMEOUT,
     )
-    mock_notify.assert_called_once_with(
-        room_name=str(room.pk), notification_data={"type": "participantWaiting"}
-    )
 
 
-# pylint: disable=R0917
-@mock.patch("core.services.lobby.cache")
-@mock.patch("core.utils.generate_color")
 @mock.patch("core.utils.notify_participants")
-def test_enter_with_notification_error(
-    mock_notify,
-    mock_generate_color,
-    mock_cache,
-    lobby_service,
-    participant_id,
-    username,
-):
-    """Test participant entry with notification error."""
-    mock_generate_color.return_value = "#123456"
+def test_notify_entry_request_with_notification_error(mock_notify, lobby_service):
+    """A notification error must not break the entry request flow."""
     mock_notify.side_effect = NotificationError("Error notifying")
-    lobby_service._get_cache_key = mock.Mock(return_value="mocked_cache_key")
 
-    room = RoomFactory(access_level=RoomAccessLevel.RESTRICTED)
-    participant = lobby_service.enter(room.id, participant_id, username)
+    lobby_service._notify_entry_request("room-id")
 
-    mock_generate_color.assert_called_once_with(participant_id)
-    assert participant.status == LobbyParticipantStatus.WAITING
-    assert participant.username == username
-
-    lobby_service._get_cache_key.assert_called_once_with(room.id, participant_id)
-
-    mock_cache.set.assert_called_once_with(
-        "mocked_cache_key",
-        participant.to_dict(),
-        timeout=settings.LOBBY_WAITING_TIMEOUT,
+    mock_notify.assert_called_once_with(
+        room_name="room-id", notification_data={"type": "participantWaiting"}
     )
 
 

src/backend/core/tests/services/test_transit_code.py

@@ -0,0 +1,46 @@
+"""
+Unit tests for the TransitCodeService.
+"""
+
+import pytest
+
+from core.factories import UserFactory
+from core.services.transit_code import TransitCodeService
+
+pytestmark = pytest.mark.django_db
+
+
+def test_create_code_returns_unique_opaque_codes():
+    """Each created code should be a distinct high-entropy string."""
+    user = UserFactory()
+    service = TransitCodeService()
+
+    codes = {service.create_code(user) for _ in range(5)}
+
+    assert len(codes) == 5
+    for code in codes:
+        assert len(code) >= 43
+
+
+def test_consume_code_returns_stored_data_once():
+    """Consuming a code should return its data exactly once."""
+    user = UserFactory()
+    service = TransitCodeService()
+
+    code = service.create_code(user, client_id="my-app")
+
+    assert service.consume_code(code) == {
+        "user_id": str(user.id),
+        "client_id": "my-app",
+    }
+    # Single use: a second consumption fails
+    assert service.consume_code(code) is None
+
+
+def test_consume_code_unknown_or_empty():
+    """Unknown or empty codes should not be consumable."""
+    service = TransitCodeService()
+
+    assert service.consume_code("unknown-code") is None
+    assert service.consume_code("") is None
+    assert service.consume_code(None) is None

src/backend/core/tests/test_api_user_access_token_authentication.py

@@ -0,0 +1,200 @@
+"""
+Tests for user access JWT authentication on the core API.
+
+The token authenticates the user on the whole API, exactly like a session
+cookie would (similar to lib-jitsi-meet's token authentication): the
+existing role-based permissions apply unchanged. Room endpoint coverage
+with a user access token lives in the room test files.
+"""
+
+from datetime import datetime, timedelta, timezone
+
+from django.conf import settings as django_settings
+
+import jwt
+import pytest
+from rest_framework.test import APIClient
+
+from core.factories import RoomFactory, UserFactory
+from core.models import RoleChoices
+
+pytestmark = pytest.mark.django_db
+
+
+def generate_user_access_token(user, **overrides):
+    """Generate a valid user access JWT signed with the token secret."""
+    now = datetime.now(timezone.utc)
+
+    payload = {
+        "iss": django_settings.USER_ACCESS_TOKEN_ISSUER,
+        "aud": django_settings.USER_ACCESS_TOKEN_AUDIENCE,
+        "iat": now,
+        "exp": now + timedelta(seconds=django_settings.USER_ACCESS_TOKEN_TTL),
+        "user_id": str(user.id),
+        "token_type": "user_access",
+        "client_id": "test-app",
+        "scope": "user:access",
+    }
+    payload.update(overrides)
+    payload = {key: value for key, value in payload.items() if value is not None}
+
+    return jwt.encode(
+        payload,
+        django_settings.USER_ACCESS_TOKEN_SECRET_KEY,
+        algorithm=django_settings.USER_ACCESS_TOKEN_ALG,
+    )
+
+
+def test_user_access_token_users_me():
+    """A user access token should authenticate the user on /users/me/."""
+    user = UserFactory()
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {generate_user_access_token(user)}")
+
+    response = client.get("/api/v1.0/users/me/")
+
+    assert response.status_code == 200
+    assert response.data["email"] == user.email
+
+
+def test_user_access_token_expired():
+    """An expired user access token should be rejected."""
+    user = UserFactory()
+
+    now = datetime.now(timezone.utc)
+    token = generate_user_access_token(
+        user,
+        iat=now - timedelta(hours=3),
+        exp=now - timedelta(hours=1),
+    )
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+
+    response = client.get("/api/v1.0/users/me/")
+
+    assert response.status_code == 401
+    assert "token expired" in str(response.data).lower()
+
+
+def test_user_access_token_invalid_signature():
+    """A token signed with the wrong key should defer and end unauthenticated."""
+    user = UserFactory()
+
+    now = datetime.now(timezone.utc)
+    token = jwt.encode(
+        {
+            "iss": django_settings.USER_ACCESS_TOKEN_ISSUER,
+            "aud": django_settings.USER_ACCESS_TOKEN_AUDIENCE,
+            "iat": now,
+            "exp": now + timedelta(seconds=600),
+            "user_id": str(user.id),
+            "token_type": "user_access",
+            "client_id": "test-app",
+        },
+        "wrong-secret-key-padded-for-minimum-len!",
+        algorithm=django_settings.USER_ACCESS_TOKEN_ALG,
+    )
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+
+    # UserAccessJWTAuthentication defers, session auth finds no session
+    response = client.get("/api/v1.0/users/me/")
+
+    assert response.status_code == 401
+
+
+def test_user_access_token_wrong_token_type():
+    """A verified token with the wrong 'token_type' claim should be rejected."""
+    user = UserFactory()
+
+    token = generate_user_access_token(user, token_type="addons")
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+
+    response = client.get("/api/v1.0/users/me/")
+
+    assert response.status_code == 401
+    assert "invalid token type" in str(response.data).lower()
+
+
+def test_user_access_token_missing_client_id_claim():
+    """A token without the issuance-audit claim should be rejected."""
+    user = UserFactory()
+
+    token = generate_user_access_token(user, client_id=None)
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+
+    response = client.get("/api/v1.0/users/me/")
+
+    assert response.status_code == 401
+    assert "invalid token claims" in str(response.data).lower()
+
+
+def test_user_access_token_inactive_user():
+    """A user access token for an inactive user should be rejected."""
+    user = UserFactory(is_active=False)
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {generate_user_access_token(user)}")
+
+    response = client.get("/api/v1.0/users/me/")
+
+    assert response.status_code == 401
+
+
+def test_user_access_token_feature_disabled(settings):
+    """When the feature is disabled, user access tokens should be ignored."""
+    settings.USER_ACCESS_TOKEN_ENABLED = False
+
+    user = UserFactory()
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {generate_user_access_token(user)}")
+
+    response = client.get("/api/v1.0/users/me/")
+
+    assert response.status_code == 401
+
+
+def test_user_access_token_does_not_break_session_authentication():
+    """A session-authenticated user should keep full access to the API."""
+    user = UserFactory()
+    RoomFactory(users=[(user, RoleChoices.OWNER)])
+
+    client = APIClient()
+    client.force_login(user)
+    response = client.get("/api/v1.0/rooms/")
+
+    assert response.status_code == 200
+    assert response.data["count"] == 1
+
+
+def test_user_access_token_application_jwt_not_accepted_on_core_api():
+    """An application-delegation JWT must not authenticate on the core API."""
+    user = UserFactory()
+
+    now = datetime.now(timezone.utc)
+    token = jwt.encode(
+        {
+            "iss": django_settings.APPLICATION_JWT_ISSUER,
+            "aud": django_settings.APPLICATION_JWT_AUDIENCE,
+            "iat": now,
+            "exp": now + timedelta(seconds=600),
+            "user_id": str(user.id),
+            "client_id": "some-client",
+            "delegated": True,
+            "scope": "rooms:retrieve",
+        },
+        django_settings.APPLICATION_JWT_SECRET_KEY,
+        algorithm=django_settings.APPLICATION_JWT_ALG,
+    )
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+
+    # The user token backend must defer (wrong signature) and the request
+    # must end up unauthenticated.
+    response = client.get("/api/v1.0/users/me/")
+
+    assert response.status_code == 401

src/backend/core/tests/test_api_users_exchange_access_token.py

@@ -0,0 +1,165 @@
+"""
+Test users API endpoints in the Meet core app: exchange transit code.
+"""
+
+# pylint: disable=W0621
+
+import secrets
+
+import jwt
+import pytest
+from rest_framework.test import APIClient
+
+from core.factories import UserFactory
+from core.services.transit_code import TransitCodeService
+
+pytestmark = pytest.mark.django_db
+
+
+def decode_user_access_token(token, settings):
+    """Decode a user access token with the token secret."""
+    return jwt.decode(
+        token,
+        settings.USER_ACCESS_TOKEN_SECRET_KEY,
+        algorithms=[settings.USER_ACCESS_TOKEN_ALG],
+        issuer=settings.USER_ACCESS_TOKEN_ISSUER,
+        audience=settings.USER_ACCESS_TOKEN_AUDIENCE,
+    )
+
+
+def generate_unknown_code(settings):
+    """Generate a well-formed code that was never stored."""
+    return secrets.token_urlsafe(settings.TRANSIT_CODE_NBYTES)
+
+
+@pytest.fixture
+def client():
+    """Return an anonymous API client with a random source IP.
+
+    A fresh IP per test isolates the anonymous throttle history, both
+    between the tests of this module and between test runs.
+    """
+    # `secrets` rather than `random`: the global random module is seeded
+    # deterministically by the factories, its sequence repeats across runs.
+    remote_addr = (
+        f"10.{secrets.randbelow(256)}.{secrets.randbelow(256)}"
+        f".{secrets.randbelow(254) + 1}"
+    )
+    return APIClient(REMOTE_ADDR=remote_addr)
+
+
+def test_exchange_access_token_missing_code(client):
+    """The exchange endpoint should validate its input."""
+    response = client.post("/api/v1.0/users/exchange-access-token/")
+
+    assert response.status_code == 400
+    assert "code" in response.data
+
+
+def test_exchange_access_token_malformed_code(client):
+    """A code whose length cannot match a generated one should be a 400."""
+    response = client.post(
+        "/api/v1.0/users/exchange-access-token/",
+        {"code": "not-a-valid-code"},
+    )
+
+    assert response.status_code == 400
+    assert "invalid transit code format" in str(response.data).lower()
+
+
+def test_exchange_access_token_unknown_code(client, settings):
+    """A well-formed but unknown code should be denied."""
+    response = client.post(
+        "/api/v1.0/users/exchange-access-token/",
+        {"code": generate_unknown_code(settings)},
+    )
+
+    assert response.status_code == 403
+    assert "invalid, expired or already used" in str(response.data).lower()
+
+
+def test_exchange_access_token_success(client, settings):
+    """A valid transit code should be exchangeable for an access token."""
+    user = UserFactory()
+
+    code = TransitCodeService().create_code(user, client_id="my-app")
+
+    response = client.post("/api/v1.0/users/exchange-access-token/", {"code": code})
+
+    assert response.status_code == 200
+    assert response.data["token_type"] == settings.USER_ACCESS_TOKEN_TYPE
+    assert response.data["expires_in"] == settings.USER_ACCESS_TOKEN_TTL
+    assert response.data["scope"] == "user:access"
+
+    payload = decode_user_access_token(response.data["access_token"], settings)
+    assert payload["token_type"] == "user_access"
+    assert payload["user_id"] == str(user.id)
+    assert payload["client_id"] == "my-app"
+    assert payload["exp"] - payload["iat"] == settings.USER_ACCESS_TOKEN_TTL
+
+
+def test_exchange_access_token_single_use(client):
+    """A transit code should be exchangeable exactly once."""
+    user = UserFactory()
+
+    code = TransitCodeService().create_code(user)
+
+    response = client.post("/api/v1.0/users/exchange-access-token/", {"code": code})
+    assert response.status_code == 200
+
+    # Replaying the same code must be denied
+    response = client.post("/api/v1.0/users/exchange-access-token/", {"code": code})
+    assert response.status_code == 403
+    assert "invalid, expired or already used" in str(response.data).lower()
+
+
+def test_exchange_access_token_inactive_user(client):
+    """A code minted for a now-inactive user should be denied."""
+    user = UserFactory()
+
+    code = TransitCodeService().create_code(user)
+
+    user.is_active = False
+    user.save()
+
+    response = client.post("/api/v1.0/users/exchange-access-token/", {"code": code})
+
+    assert response.status_code == 403
+    assert "no longer access" in str(response.data).lower()
+
+
+def test_exchange_access_token_feature_disabled(client, settings):
+    """The exchange endpoint should return 404 when the feature is disabled."""
+    settings.USER_ACCESS_TOKEN_ENABLED = False
+
+    user = UserFactory()
+    code = TransitCodeService().create_code(user)
+
+    response = client.post("/api/v1.0/users/exchange-access-token/", {"code": code})
+
+    assert response.status_code == 404
+
+
+def test_exchange_access_token_throttled(client, settings):
+    """Anonymous exchange attempts should be rate limited."""
+    throttle_rates = settings.REST_FRAMEWORK["DEFAULT_THROTTLE_RATES"]
+    initial_rate = throttle_rates["exchange_access_token"]
+    # The rates dict is mutated in place: restore it explicitly, the
+    # `settings` fixture only rolls back attribute assignments.
+    throttle_rates["exchange_access_token"] = "2/minute"
+
+    try:
+        for _ in range(2):
+            response = client.post(
+                "/api/v1.0/users/exchange-access-token/",
+                {"code": generate_unknown_code(settings)},
+            )
+            assert response.status_code == 403
+
+        response = client.post(
+            "/api/v1.0/users/exchange-access-token/",
+            {"code": generate_unknown_code(settings)},
+        )
+        assert response.status_code == 429
+    finally:
+        throttle_rates["exchange_access_token"] = initial_rate

src/backend/core/tests/test_external_api_users.py

@@ -0,0 +1,166 @@
+"""
+Tests for external API /users endpoints (transit codes)
+"""
+
+# pylint: disable=W0621
+
+from datetime import datetime, timedelta, timezone
+from unittest import mock
+
+from django.conf import settings as django_settings
+
+import jwt
+import pytest
+from lasuite.oidc_resource_server.authentication import ResourceServerAuthentication
+from rest_framework.test import APIClient
+
+from core.factories import ApplicationFactory, UserFactory
+from core.models import ApplicationScope
+from core.services.transit_code import TransitCodeService
+
+pytestmark = pytest.mark.django_db
+
+
+def generate_test_token(user, scopes):
+    """Generate a valid application JWT token for testing."""
+    now = datetime.now(timezone.utc)
+    scope_string = " ".join(scopes)
+
+    application = ApplicationFactory()
+
+    payload = {
+        "iss": django_settings.APPLICATION_JWT_ISSUER,
+        "aud": django_settings.APPLICATION_JWT_AUDIENCE,
+        "iat": now,
+        "exp": now
+        + timedelta(seconds=django_settings.APPLICATION_JWT_EXPIRATION_SECONDS),
+        "client_id": str(application.client_id),
+        "scope": scope_string,
+        "user_id": str(user.id),
+        "delegated": True,
+    }
+
+    return jwt.encode(
+        payload,
+        django_settings.APPLICATION_JWT_SECRET_KEY,
+        algorithm=django_settings.APPLICATION_JWT_ALG,
+    )
+
+
+def test_api_users_transit_code_requires_authentication():
+    """Minting a transit code without authentication should return 401."""
+    client = APIClient()
+    response = client.post("/external-api/v1.0/users/transit-code/")
+
+    assert response.status_code == 401
+
+
+def test_api_users_transit_code_missing_scope():
+    """A token without the 'users:session' scope should be rejected."""
+    user = UserFactory()
+
+    token = generate_test_token(user, [ApplicationScope.ROOMS_RETRIEVE])
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+    response = client.post("/external-api/v1.0/users/transit-code/")
+
+    assert response.status_code == 403
+    assert "users:session" in str(response.data)
+
+
+def test_api_users_transit_code_success(settings):
+    """A delegated user with the scope should be able to mint a transit code."""
+    user = UserFactory()
+
+    token = generate_test_token(user, [ApplicationScope.USERS_SESSION])
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+    response = client.post("/external-api/v1.0/users/transit-code/")
+
+    assert response.status_code == 200
+    assert response.data["expires_in"] == settings.TRANSIT_CODE_TTL
+
+    code = response.data["transit_code"]
+    # Opaque, high-entropy random string
+    assert len(code) == (4 * settings.TRANSIT_CODE_NBYTES + 2) // 3
+
+    # The code is stored server-side and references the delegated user
+    code_data = TransitCodeService().consume_code(code)
+    assert code_data == {
+        "user_id": str(user.id),
+        "client_id": mock.ANY,
+    }
+
+
+def test_api_users_transit_code_with_rs_token():
+    """A resource-server-authenticated user should be able to mint a code."""
+    user = UserFactory()
+
+    # todo - add a decorator instead
+    with mock.patch.object(
+        ResourceServerAuthentication,
+        "authenticate",
+        return_value=(user, {"scope": "users:session", "client_id": "rs-client"}),
+    ) as mock_rs_authenticate:
+        client = APIClient()
+        client.credentials(HTTP_AUTHORIZATION="Bearer some-opaque-rs-token")
+        response = client.post("/external-api/v1.0/users/transit-code/")
+
+    mock_rs_authenticate.assert_called_once()
+    assert response.status_code == 200
+
+    code_data = TransitCodeService().consume_code(response.data["transit_code"])
+    assert code_data == {
+        "user_id": str(user.id),
+        "client_id": "rs-client",
+    }
+
+
+def test_api_users_transit_code_with_rs_token_missing_scope():
+    """A resource server token without the scope should be rejected."""
+    user = UserFactory()
+
+    # todo - add a decorator instead
+    with mock.patch.object(
+        ResourceServerAuthentication,
+        "authenticate",
+        return_value=(user, {"scope": "rooms:list", "client_id": "rs-client"}),
+    ):
+        client = APIClient()
+        client.credentials(HTTP_AUTHORIZATION="Bearer some-opaque-rs-token")
+        response = client.post("/external-api/v1.0/users/transit-code/")
+
+    assert response.status_code == 403
+    assert "users:session" in str(response.data)
+
+
+def test_api_users_transit_code_feature_disabled(settings):
+    """Minting a transit code should return 404 when the feature is disabled."""
+    settings.USER_ACCESS_TOKEN_ENABLED = False
+
+    user = UserFactory()
+    token = generate_test_token(user, [ApplicationScope.USERS_SESSION])
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+    response = client.post("/external-api/v1.0/users/transit-code/")
+
+    assert response.status_code == 404
+
+
+def test_api_users_transit_code_inactive_user():
+    """An inactive user should not be able to mint a transit code."""
+    user = UserFactory(is_active=False)
+
+    token = generate_test_token(user, [ApplicationScope.USERS_SESSION])
+
+    client = APIClient()
+    client.credentials(HTTP_AUTHORIZATION=f"Bearer {token}")
+    response = client.post("/external-api/v1.0/users/transit-code/")
+
+    assert response.status_code == 401
+
+
+# todo - add a test to make sure the addon authentification doesn't allow to mint a transit token

src/backend/core/urls.py

@@ -37,6 +37,11 @@ external_router.register(
     external_viewsets.RoomViewSet,
     basename="external_room",
 )
+external_router.register(
+    "users",
+    external_viewsets.UserViewSet,
+    basename="external_user",
+)
 
 urlpatterns = [
     path(

src/backend/meet/settings.py

@@ -324,6 +324,7 @@ class Base(Configuration):
 
     REST_FRAMEWORK = {
         "DEFAULT_AUTHENTICATION_CLASSES": (
+            "core.authentication.user_token.UserAccessJWTAuthentication",
             "core.authentication.backends.SessionAuthenticationWith401",
         ),
         "DEFAULT_PARSER_CLASSES": [
@@ -344,6 +345,11 @@ class Base(Configuration):
                 environ_name="REQUEST_ENTRY_THROTTLE_RATES",
                 environ_prefix=None,
             ),
+            "exchange_access_token": values.Value(
+                default="30/minute",
+                environ_name="EXCHANGE_ACCESS_TOKEN_THROTTLE_RATES",
+                environ_prefix=None,
+            ),
             "creation_callback": values.Value(
                 default="600/minute",
                 environ_name="CREATION_CALLBACK_THROTTLE_RATES",
@@ -841,11 +847,6 @@ class Base(Configuration):
         environ_name="LOBBY_NOTIFICATION_TYPE",
         environ_prefix=None,
     )
-    LOBBY_COOKIE_NAME = values.Value(
-        "lobbyParticipantId",
-        environ_name="LOBBY_COOKIE_NAME",
-        environ_prefix=None,
-    )
 
     # Calendar integrations
     ROOM_CREATION_CALLBACK_CACHE_TIMEOUT = values.PositiveIntegerValue(
@@ -953,6 +954,61 @@ class Base(Configuration):
         environ_name="APPLICATION_BASE_URL",
         environ_prefix=None,
     )
+
+    # User access tokens (embedded frontend / iframe support)
+    USER_ACCESS_TOKEN_ENABLED = values.BooleanValue(
+        False, environ_name="USER_ACCESS_TOKEN_ENABLED", environ_prefix=None
+    )
+    USER_ACCESS_TOKEN_SECRET_KEY = SecretFileValue(
+        None, environ_name="USER_ACCESS_TOKEN_SECRET_KEY", environ_prefix=None
+    )
+    USER_ACCESS_TOKEN_ALG = values.Value(
+        "HS256",
+        environ_name="USER_ACCESS_TOKEN_ALG",
+        environ_prefix=None,
+    )
+    USER_ACCESS_TOKEN_ISSUER = values.Value(
+        "lasuite-meet",
+        environ_name="USER_ACCESS_TOKEN_ISSUER",
+        environ_prefix=None,
+    )
+    USER_ACCESS_TOKEN_AUDIENCE = values.Value(
+        None,
+        environ_name="USER_ACCESS_TOKEN_AUDIENCE",
+        environ_prefix=None,
+    )
+    # Lifetime of the user access token obtained through the exchange
+    # endpoint. It never transits through a URL, so it can cover a full
+    # meeting (default: 2 hours).
+    USER_ACCESS_TOKEN_TTL = values.PositiveIntegerValue(
+        7200,
+        environ_name="USER_ACCESS_TOKEN_TTL",
+        environ_prefix=None,
+    )
+    # Lifetime of the single-use transit code handed to the frontend
+    # through a URL fragment. Kept very short by design: it must only
+    # survive the redirect and the exchange call.
+    TRANSIT_CODE_TTL = values.PositiveIntegerValue(
+        60,
+        environ_name="TRANSIT_CODE_TTL",
+        environ_prefix=None,
+    )
+    TRANSIT_CODE_CACHE_PREFIX = values.Value(
+        "transit-code",
+        environ_name="TRANSIT_CODE_CACHE_PREFIX",
+        environ_prefix=None,
+    )
+    # Number of random bytes per code (48 bytes -> 64 url-safe characters)
+    TRANSIT_CODE_NBYTES = values.PositiveIntegerValue(
+        48,
+        environ_name="TRANSIT_CODE_NBYTES",
+        environ_prefix=None,
+    )
+    USER_ACCESS_TOKEN_TYPE = values.Value(
+        "Bearer",
+        environ_name="USER_ACCESS_TOKEN_TYPE",
+        environ_prefix=None,
+    )
     # Warning: EXTERNAL_API_ALLOW_PUBLIC_ACCESS is ignored when
     # EXTERNAL_API_DEFAULT_ACCESS_LEVEL=public.
     EXTERNAL_API_ALLOW_PUBLIC_ACCESS = values.BooleanValue(
@@ -1250,6 +1306,10 @@ class Test(Base):
     ADDONS_CSRF_SECRET = "secret-key-padded-for-minimum-len!-addons"  # noqa:S105
     ADDONS_TOKEN_SECRET_KEY = "secret-key-padded-for-minimum-len!-addons"  # noqa:S105
 
+    USER_ACCESS_TOKEN_ENABLED = True
+    USER_ACCESS_TOKEN_SECRET_KEY = "secret-key-padded-for-minimum-len!-room"  # noqa:S105
+    USER_ACCESS_TOKEN_AUDIENCE = "Test inc."  # noqa:S105
+
     def __init__(self):
         # pylint: disable=invalid-name
         self.INSTALLED_APPS += ["drf_spectacular_sidecar"]

src/frontend/src/App.tsx

@@ -12,6 +12,7 @@ import { routes } from './routes'
 import './i18n/init'
 import { queryClient } from '@/api/queryClient'
 import { AppInitialization } from '@/components/AppInitialization'
+import { TransitCodeGate } from '@/features/auth/components/TransitCodeGate'
 import { useIsSdkContext } from '@/features/sdk/hooks/useIsSdkContext'
 import { useApplyA11yFonts } from '@/hooks/useApplyA11yFonts'
 
@@ -24,23 +25,29 @@ function App() {
 
   return (
     <QueryClientProvider client={queryClient}>
-      {!isSDKContext && <AppInitialization />}
-      <Suspense fallback={null}>
-        <I18nProvider locale={i18n.language}>
-          <Layout>
-            <Switch>
-              {Object.entries(routes).map(([, route], i) => (
-                <Route key={i} path={route.path} component={route.Component} />
-              ))}
-              <Route component={NotFoundScreen} />
-            </Switch>
-          </Layout>
-          <ReactQueryDevtools
-            initialIsOpen={false}
-            buttonPosition="bottom-left"
-          />
-        </I18nProvider>
-      </Suspense>
+      <TransitCodeGate>
+        {!isSDKContext && <AppInitialization />}
+        <Suspense fallback={null}>
+          <I18nProvider locale={i18n.language}>
+            <Layout>
+              <Switch>
+                {Object.entries(routes).map(([, route], i) => (
+                  <Route
+                    key={i}
+                    path={route.path}
+                    component={route.Component}
+                  />
+                ))}
+                <Route component={NotFoundScreen} />
+              </Switch>
+            </Layout>
+            <ReactQueryDevtools
+              initialIsOpen={false}
+              buttonPosition="bottom-left"
+            />
+          </I18nProvider>
+        </Suspense>
+      </TransitCodeGate>
     </QueryClientProvider>
   )
 }

src/frontend/src/api/fetchApi.ts

@@ -1,17 +1,23 @@
 import { ApiError } from './ApiError'
 import { apiUrl } from './apiUrl'
+import { getAccessToken } from '@/stores/accessToken'
 
 export const fetchApi = async <T = Record<string, unknown>>(
   url: string,
   options?: RequestInit
 ): Promise<T> => {
   const csrfToken = getCsrfToken()
+  // Embedded (iframe) mode: the user access token obtained through the
+  // transit code exchange authenticates requests in place of the session
+  // cookie, which is blocked in third-party contexts.
+  const accessToken = getAccessToken()
   const response = await fetch(apiUrl(url), {
     credentials: 'include',
     ...options,
     headers: {
       'Content-Type': 'application/json',
       ...(!!csrfToken && { 'X-CSRFToken': csrfToken }),
+      ...(!!accessToken && { Authorization: `Bearer ${accessToken}` }),
       ...options?.headers,
     },
   })

src/frontend/src/features/auth/api/exchangeAccessToken.ts

@@ -0,0 +1,64 @@
+import { fetchApi } from '@/api/fetchApi'
+import { setAccessToken } from '@/stores/accessToken'
+import { consumeTransitCodeFromFragment } from '../utils/transitCode'
+
+type ApiAccessToken = {
+  access_token: string
+  token_type: string
+  expires_in: number
+  scope: string
+}
+
+/**
+ * Exchange a single-use transit code for a user access token.
+ *
+ * The endpoint is unauthenticated: the code itself is the credential.
+ */
+export const exchangeAccessToken = (code: string): Promise<ApiAccessToken> => {
+  return fetchApi<ApiAccessToken>('/users/exchange-access-token/', {
+    method: 'POST',
+    body: JSON.stringify({ code }),
+  })
+}
+
+const runInitialization = async (): Promise<void> => {
+  const code = consumeTransitCodeFromFragment()
+
+  if (!code) {
+    return
+  }
+
+  try {
+    const { access_token } = await exchangeAccessToken(code)
+    setAccessToken(access_token)
+  } catch (error) {
+    console.warn('Transit code exchange failed:', error)
+  }
+}
+
+let initialization: Promise<void> | null = null
+
+/**
+ * Bootstrap the embedded (iframe) authentication, if applicable.
+ *
+ * When, and only when, a transit code is present in the URL fragment,
+ * exchange it for a user access token and keep it in the in-memory
+ * accessToken store: fetchApi then sends it as a Bearer header on every
+ * api call, authenticating the user exactly like a session cookie would.
+ *
+ * Must complete before anything fires an authenticated query, which the
+ * TransitCodeGate component guarantees by gating the app tree on it.
+ *
+ * Memoized: the fragment is consumed and the code exchanged exactly once,
+ * however many times this is called (StrictMode double-invoked effects,
+ * among others). Subsequent calls await the same promise.
+ *
+ * A failed exchange (expired or already used code) is not fatal: the app
+ * starts unauthenticated, falling back to the regular session flow.
+ */
+export const initializeAccessTokenFromFragment = (): Promise<void> => {
+  if (!initialization) {
+    initialization = runInitialization()
+  }
+  return initialization
+}

src/frontend/src/features/auth/api/fetchUser.ts

@@ -2,6 +2,7 @@ import { ApiError } from '@/api/ApiError'
 import { fetchApi } from '@/api/fetchApi'
 import { type ApiUser } from './ApiUser'
 import { attemptSilentLogin, canAttemptSilentLogin } from '../utils/silentLogin'
+import { getAccessToken } from '@/stores/accessToken'
 
 /**
  * fetch the logged-in user from the api.
@@ -25,7 +26,13 @@ export const fetchUser = (
         if (error instanceof ApiError && error.statusCode === 401) {
           // make sure to not resolve the promise while trying to silent login
           // so that consumers of fetchUser don't think the work already ended
-          if (opts.attemptSilent && canAttemptSilentLogin()) {
+          // Never attempt a silent login in embedded (token) mode: an OIDC
+          // redirect inside the iframe would break the embed.
+          if (
+            opts.attemptSilent &&
+            !getAccessToken() &&
+            canAttemptSilentLogin()
+          ) {
             attemptSilentLogin(30)
           } else {
             resolve(false)

src/frontend/src/features/auth/components/TransitCodeGate.tsx

@@ -0,0 +1,67 @@
+import { useEffect, useState } from 'react'
+import { LoadingScreen } from '@/components/LoadingScreen'
+import { useHash } from '@/hooks/useHash'
+import { initializeAccessTokenFromFragment } from '../api/exchangeAccessToken'
+import { hasTransitCodeInFragment } from '../utils/transitCode'
+
+/**
+ * Gates the app tree on the embedded (iframe) authentication bootstrap.
+ *
+ * Without a transit code in the URL fragment — the overwhelmingly common
+ * case — the component early returns children synchronously: no state,
+ * no effect, no extra render, no loading screen.
+ *
+ * When a transit code is present, children are not mounted until it has
+ * been exchanged for a user access token, so that every authenticated
+ * query already carries the Authorization header. A loading screen is
+ * displayed in the meantime, as UserAware does.
+ */
+export const TransitCodeGate = ({
+  children,
+}: {
+  children: React.ReactNode
+}) => {
+  const hash = useHash()
+
+  // Latch the decision on the initial hash: the bootstrap scrubs the
+  // fragment as soon as it starts, and the gate must not flip back to the
+  // fast path while the exchange is still in flight.
+  const [needsExchange] = useState(() => hasTransitCodeInFragment(hash))
+
+  if (!needsExchange) {
+    return children
+  }
+
+  return <TransitCodeExchange>{children}</TransitCodeExchange>
+}
+
+/**
+ * Only ever mounted when a transit code is present: runs the memoized
+ * bootstrap (safe against StrictMode double-invoked effects) and holds
+ * children back until it settles.
+ */
+const TransitCodeExchange = ({ children }: { children: React.ReactNode }) => {
+  const [isReady, setIsReady] = useState(false)
+
+  useEffect(() => {
+    let isMounted = true
+    initializeAccessTokenFromFragment().finally(() => {
+      console.log('$$ transit code exchange finished')
+      if (isMounted) {
+        console.log('$$ setIsReady')
+        setIsReady(true)
+      }
+    })
+    return () => {
+      isMounted = false
+    }
+  }, [])
+
+  console.log('$$ isReady', isReady)
+
+  return isReady ? (
+    children
+  ) : (
+    <LoadingScreen header={false} footer={false} delay={1000} />
+  )
+}

src/frontend/src/features/auth/utils/transitCode.ts

@@ -0,0 +1,46 @@
+const TRANSIT_CODE_FRAGMENT_PARAM = 'transit_code'
+
+/**
+ * Whether a URL fragment carries a transit code. Pure check, does not
+ * consume anything.
+ */
+export const hasTransitCodeInFragment = (hash: string): boolean => {
+  if (!hash) {
+    return false
+  }
+  return new URLSearchParams(hash.replace(/^#/, '')).has(
+    TRANSIT_CODE_FRAGMENT_PARAM
+  )
+}
+
+/**
+ * Extract the transit code from the URL fragment, if any.
+ *
+ * The fragment is scrubbed from the address bar immediately, before any
+ * network call, so the code never lingers in the browser history. Any
+ * other fragment content is preserved.
+ */
+export const consumeTransitCodeFromFragment = (): string | null => {
+  if (typeof window === 'undefined' || !window.location.hash) {
+    return null
+  }
+
+  const params = new URLSearchParams(window.location.hash.substring(1))
+  const code = params.get(TRANSIT_CODE_FRAGMENT_PARAM)
+
+  if (!code) {
+    return null
+  }
+
+  params.delete(TRANSIT_CODE_FRAGMENT_PARAM)
+  const remaining = params.toString()
+  window.history.replaceState(
+    null,
+    '',
+    window.location.pathname +
+      window.location.search +
+      (remaining ? `#${remaining}` : '')
+  )
+
+  return code
+}

src/frontend/src/features/files/hooks/useResolvedMediaUrls.ts

@@ -0,0 +1,56 @@
+import { useCallback, useEffect, useState } from 'react'
+import { useSnapshot } from 'valtio'
+import { accessTokenStore } from '@/stores/accessToken'
+import { resolveMediaUrl } from '../utils/resolveMediaUrl'
+
+/**
+ * Reactive companion of resolveMediaUrl for browser-native consumers
+ * (CSS url(), img src attributes): resolves a list of /media/ URLs and
+ * returns a stable lookup, identity in regular mode.
+ *
+ * Object URLs come from the shared session-lifetime cache and are never
+ * revoked here: they may be used concurrently by the background
+ * processors.
+ */
+export const useResolvedMediaUrls = (
+  urls: (string | null | undefined)[]
+): ((url: string) => string) => {
+  const [resolved, setResolved] = useState<Record<string, string>>({})
+  const { accessToken } = useSnapshot(accessTokenStore)
+
+  // Stable dependency for the effect, insensitive to array identity
+  const urlsKey = urls.filter(Boolean).sort().join('\n')
+
+  useEffect(() => {
+    if (!accessToken || !urlsKey) {
+      return
+    }
+
+    let isMounted = true
+
+    const resolveAll = async () => {
+      const entries = await Promise.all(
+        urlsKey.split('\n').map(async (url) => {
+          try {
+            return [url, await resolveMediaUrl(url)] as const
+          } catch (error) {
+            console.warn(error)
+            return [url, url] as const
+          }
+        })
+      )
+      if (isMounted) {
+        setResolved(Object.fromEntries(entries))
+      }
+    }
+    resolveAll()
+
+    return () => {
+      isMounted = false
+    }
+  }, [accessToken, urlsKey])
+
+  // Stable identity so that consumers can safely list the resolver in
+  // their memo dependencies: it only changes when resolutions land.
+  return useCallback((url: string) => resolved[url] ?? url, [resolved])
+}

src/frontend/src/features/files/utils/resolveMediaUrl.ts

@@ -0,0 +1,47 @@
+import { getAccessToken } from '@/stores/accessToken'
+
+// Session-lifetime cache: object URLs are shared between every consumer
+// of a given media (background processors, thumbnails) and are therefore
+// never revoked - their number is bounded by the user's custom
+// backgrounds, and they die with the page like the access token does.
+const objectUrlCache = new Map<string, string>()
+
+/**
+ * Resolve an authenticated /media/ URL for the embedded (token) mode.
+ *
+ * Media files are served behind an nginx auth_request subrequest that
+ * authenticates the original request. In regular mode the session cookie
+ * rides along browser-native loads (img.src, CSS url()) and the URL is
+ * returned unchanged, without any fetch. In embedded mode the
+ * third-party cookie is blocked and native loads cannot carry the
+ * Authorization header, so the media is fetched here with the Bearer
+ * header - which the media-auth endpoint accepts, as it sits behind the
+ * default authentication stack - and exposed as a blob object URL.
+ */
+export const resolveMediaUrl = async (url: string): Promise<string> => {
+  const accessToken = getAccessToken()
+
+  if (!accessToken) {
+    return url
+  }
+
+  const cached = objectUrlCache.get(url)
+  if (cached) {
+    return cached
+  }
+
+  const response = await fetch(url, {
+    headers: { Authorization: `Bearer ${accessToken}` },
+  })
+
+  if (!response.ok) {
+    throw new Error(
+      `Failed to resolve media url ${url}: HTTP ${response.status}`
+    )
+  }
+
+  const objectUrl = URL.createObjectURL(await response.blob())
+  objectUrlCache.set(url, objectUrl)
+
+  return objectUrl
+}

src/frontend/src/features/rooms/api/muteParticipant.ts

@@ -9,6 +9,7 @@ import { fetchApi } from '@/api/fetchApi'
 import { useIsAdminOrOwner } from '../livekit/hooks/useIsAdminOrOwner'
 
 import { useCallback } from 'react'
+import { getLiveKitAuthHeaders } from '../utils/getLiveKitAuthHeaders'
 
 export const useMuteParticipant = () => {
   const apiRoomData = useRoomData()
@@ -36,7 +37,7 @@ export const useMuteParticipant = () => {
       }
 
       const headers = !isAdminOrOwner
-        ? { Authorization: `Bearer ${apiRoomData.livekit.token}` }
+        ? getLiveKitAuthHeaders(apiRoomData.livekit.token)
         : undefined
 
       let response

src/frontend/src/features/rooms/api/renameParticipant.ts

@@ -1,5 +1,6 @@
 import { fetchApi } from '@/api/fetchApi'
 import { useRoomData } from '@/features/rooms/livekit/hooks/useRoomData'
+import { getLiveKitAuthHeaders } from '../utils/getLiveKitAuthHeaders'
 
 export const useRenameParticipant = () => {
   const data = useRoomData()
@@ -15,11 +16,10 @@ export const useRenameParticipant = () => {
       throw new Error('LiveKit token is not available')
     }
 
+    const headers = getLiveKitAuthHeaders(token)
     return fetchApi(`rooms/${data.id}/rename/`, {
       method: 'POST',
-      headers: {
-        Authorization: `Bearer ${token}`,
-      },
+      headers,
       body: JSON.stringify({
         name,
       }),

src/frontend/src/features/rooms/api/requestEntry.ts

@@ -1,5 +1,6 @@
 import { fetchApi } from '@/api/fetchApi'
 import type { ApiLiveKit } from '@/features/rooms/api/ApiRoom'
+import { getLobbyParticipantId } from '@/stores/lobby'
 
 export interface RequestEntryParams {
   roomId: string
@@ -15,6 +16,7 @@ export enum ApiLobbyStatus {
 }
 
 export interface ApiRequestEntry {
+  id?: string
   status: ApiLobbyStatus
   livekit?: ApiLiveKit
 }
@@ -23,10 +25,12 @@ export const requestEntry = async ({
   roomId,
   username = '',
 }: RequestEntryParams) => {
+  const participantId = getLobbyParticipantId(roomId)
   return fetchApi<ApiRequestEntry>(`/rooms/${roomId}/request-entry/`, {
     method: 'POST',
     body: JSON.stringify({
       username,
+      ...(participantId && { participant_id: participantId }),
     }),
   })
 }

src/frontend/src/features/rooms/api/updateRaiseHand.ts

@@ -1,5 +1,6 @@
 import { fetchApi } from '@/api/fetchApi'
 import { useRoomData } from '@/features/rooms/livekit/hooks/useRoomData'
+import { getLiveKitAuthHeaders } from '../utils/getLiveKitAuthHeaders'
 
 export const useRaiseHand = () => {
   const data = useRoomData()
@@ -15,11 +16,10 @@ export const useRaiseHand = () => {
       throw new Error('LiveKit token is not available')
     }
 
+    const headers = getLiveKitAuthHeaders(token)
     return fetchApi(`rooms/${data.id}/toggle-hand/`, {
       method: 'POST',
-      headers: {
-        Authorization: `Bearer ${token}`,
-      },
+      headers,
       body: JSON.stringify({
         raised,
       }),

src/frontend/src/features/rooms/hooks/useLobby.ts

@@ -6,6 +6,7 @@ import {
   ApiLobbyStatus,
   type ApiRequestEntry,
 } from '../api/requestEntry'
+import { setLobbyParticipantId } from '@/stores/lobby'
 
 export const WAIT_TIMEOUT_MS = 600000 // 10 minutes
 export const POLL_INTERVAL_MS = 1000
@@ -43,6 +44,11 @@ export const useLobby = ({
         roomId,
         username,
       })
+
+      if (response.id) {
+        setLobbyParticipantId(roomId, response.id)
+      }
+
       if (response.status === ApiLobbyStatus.ACCEPTED) {
         clearWaitingTimeout()
         setStatus(ApiLobbyStatus.ACCEPTED)

src/frontend/src/features/rooms/livekit/components/blur/BackgroundCustomProcessor.ts

@@ -1,4 +1,5 @@
 import type { ProcessorOptions, Track } from 'livekit-client'
+import { resolveMediaUrl } from '@/features/files/utils/resolveMediaUrl'
 import posthog from 'posthog-js'
 import {
   FilesetResolver,
@@ -85,7 +86,7 @@ export class BackgroundCustomProcessor implements BackgroundProcessorInterface {
     this.sourceSettings = this.source!.getSettings()
     this.videoElement = opts.element as HTMLVideoElement
 
-    this._initVirtualBackgroundImage()
+    await this._initVirtualBackgroundImage()
     this._createMainCanvas()
     this._createMaskCanvas()
 
@@ -103,7 +104,7 @@ export class BackgroundCustomProcessor implements BackgroundProcessorInterface {
     posthog.capture('firefox-blurring-init')
   }
 
-  _initVirtualBackgroundImage() {
+  async _initVirtualBackgroundImage() {
     if (this.options.type !== 'virtual') {
       throw new Error(
         'Virtual background is only supported for virtual background'
@@ -115,15 +116,19 @@ export class BackgroundCustomProcessor implements BackgroundProcessorInterface {
       this.virtualBackgroundImage &&
       this.virtualBackgroundImage.src !== this.options.imagePath
     if (this.options.imagePath || needsUpdate) {
+      // Embedded (token) mode: img.src cannot carry the Authorization
+      // header, resolve the media to a blob object URL first. Identity
+      // in regular mode.
+      const imagePath = await resolveMediaUrl(this.options.imagePath!)
       this.virtualBackgroundImage = document.createElement('img')
       this.virtualBackgroundImage.crossOrigin = 'anonymous'
-      this.virtualBackgroundImage.src = this.options.imagePath!
+      this.virtualBackgroundImage.src = imagePath
     }
   }
 
   async update(opts: ProcessorConfig): Promise<void> {
     this.options = opts
-    this._initVirtualBackgroundImage()
+    await this._initVirtualBackgroundImage()
   }
 
   _initWorker() {

src/frontend/src/features/rooms/livekit/components/blur/UnifiedBackgroundTrackProcessor.ts

@@ -1,4 +1,5 @@
 import type { ProcessorOptions, Track } from 'livekit-client'
+import { resolveMediaUrl } from '@/features/files/utils/resolveMediaUrl'
 import {
   ProcessorWrapper,
   BackgroundProcessor,
@@ -47,7 +48,16 @@ export class UnifiedBackgroundTrackProcessor implements BackgroundProcessorInter
   }
 
   async init(opts: ProcessorOptions<Track.Kind>) {
-    return this.processor.init(opts)
+    await this.processor.init(opts)
+    // Embedded (token) mode: the constructor passed the raw imagePath,
+    // whose native load cannot carry the Authorization header. Swap it
+    // for a resolved blob object URL. No-op in regular mode.
+    if (this.opts.type === 'virtual') {
+      const imagePath = await resolveMediaUrl(this.opts.imagePath)
+      if (imagePath !== this.opts.imagePath) {
+        await this.processor.updateTransformerOptions({ imagePath })
+      }
+    }
   }
 
   async restart(opts: ProcessorOptions<Track.Kind>) {
@@ -59,6 +69,9 @@ export class UnifiedBackgroundTrackProcessor implements BackgroundProcessorInter
   }
 
   async update(opts: ProcessorConfig): Promise<void> {
+    if (opts.type === 'virtual') {
+      opts = { ...opts, imagePath: await resolveMediaUrl(opts.imagePath) }
+    }
     this.opts = opts
 
     const newProcessorType =

src/frontend/src/features/rooms/livekit/components/effects/EffectsConfiguration.tsx

@@ -8,6 +8,7 @@ import {
   ProcessorType,
 } from '../blur'
 import { css } from '@/styled-system/css'
+import { useResolvedMediaUrls } from '@/features/files/hooks/useResolvedMediaUrls'
 import { Button, Dialog, H, P, Text, ToggleButton } from '@/primitives'
 import { VisualOnlyTooltip } from '@/primitives/VisualOnlyTooltip'
 import { HStack, styled } from '@/styled-system/jsx'
@@ -277,6 +278,14 @@ export const EffectsConfiguration = ({
       filesQ.data.count >= appConfig.background_image.max_count_by_user) ??
     false
 
+  // Thumbnails are browser-native loads (CSS url()) which cannot carry
+  // the Authorization header in embedded (token) mode: resolve them. The
+  // processor configs keep the stable raw URLs - they are persisted in
+  // the user choices - and the processors resolve them internally.
+  const resolveMediaUrl = useResolvedMediaUrls(
+    (filesQ.data?.results ?? []).map((file) => file.url)
+  )
+
   const getHandleSelectChangeFile = useCallback(
     (file: ApiFileItem) => {
       return async () => {
@@ -754,7 +763,7 @@ export const EffectsConfiguration = ({
                                   bgSize: 'cover',
                                 })}
                                 style={{
-                                  backgroundImage: `url(${option.file.url!})`,
+                                  backgroundImage: `url(${resolveMediaUrl(option.file.url!)})`,
                                 }}
                                 data-attr={`toggle-virtual-${option.file.id}`}
                               />

src/frontend/src/features/rooms/utils/getLiveKitAuthHeaders.ts

@@ -0,0 +1,7 @@
+const LIVEKIT_AUTH_SCHEME = 'X-LiveKit-Token'
+
+export const getLiveKitAuthHeaders = (token: string) => {
+  return {
+    Authorization: `${LIVEKIT_AUTH_SCHEME} ${token}`,
+  }
+}

src/frontend/src/features/subtitle/api/startSubtitle.ts

@@ -2,6 +2,7 @@ import { useMutation, type UseMutationOptions } from '@tanstack/react-query'
 import { fetchApi } from '@/api/fetchApi'
 import type { ApiError } from '@/api/ApiError'
 import type { ApiRoom } from '@/features/rooms/api/ApiRoom'
+import { getLiveKitAuthHeaders } from '@/features/rooms/utils/getLiveKitAuthHeaders'
 
 export interface StartSubtitleParams {
   id: string
@@ -14,9 +15,7 @@ const startSubtitle = ({
 }: StartSubtitleParams): Promise<ApiRoom> => {
   return fetchApi(`rooms/${id}/start-subtitle/`, {
     method: 'POST',
-    headers: {
-      Authorization: `Bearer ${token}`,
-    },
+    headers: getLiveKitAuthHeaders(token),
   })
 }
 

src/frontend/src/hooks/useHash.ts

@@ -0,0 +1,10 @@
+import { useLocationProperty } from 'wouter/use-browser-location'
+
+const hashSelector = () =>
+  typeof window !== 'undefined' ? window.location.hash : ''
+
+/**
+ * Reactive window.location.hash, subscribed to wouter's navigation
+ * events (the same low-level primitive wouter builds useSearch upon).
+ */
+export const useHash = (): string => useLocationProperty(hashSelector, () => '')

src/frontend/src/stores/accessToken.ts

@@ -0,0 +1,32 @@
+import { proxy } from 'valtio'
+
+type State = {
+  accessToken: string | null
+}
+
+/**
+ * User access token for the embedded (iframe) mode.
+ *
+ * When Meet is rendered inside an iframe, third-party session cookies are
+ * blocked: the host application passes a single-use transit code in the
+ * URL fragment, exchanged at startup for a user access token (see
+ * features/auth/api/exchangeAccessToken) that authenticates every api
+ * call exactly like a session cookie would.
+ *
+ * The token deliberately lives in this in-memory store only: unlike other
+ * stores, it is never persisted (no subscribe/localStorage) and never
+ * appears in a URL. It is lost on reload, in which case the host page is
+ * expected to mint a fresh transit code.
+ *
+ * A non-null token also tells the app it is running in embedded mode:
+ * components can react to it with useSnapshot(accessTokenStore).
+ */
+export const accessTokenStore = proxy<State>({
+  accessToken: null,
+})
+
+export const setAccessToken = (accessToken: string | null) => {
+  accessTokenStore.accessToken = accessToken
+}
+
+export const getAccessToken = () => accessTokenStore.accessToken

src/frontend/src/stores/lobby.ts

@@ -0,0 +1,23 @@
+import { proxy } from 'valtio'
+
+type State = {
+  participantIds: Record<string, string | undefined>
+}
+
+export const layoutStore = proxy<State>({
+  participantIds: {},
+})
+
+export const setLobbyParticipantId = (
+  roomId: string,
+  participantId: string
+) => {
+  layoutStore.participantIds[roomId] = participantId
+}
+
+export const clearParticipantId = (roomId: string) => {
+  delete layoutStore.participantIds[roomId]
+}
+
+export const getLobbyParticipantId = (roomId: string) =>
+  layoutStore.participantIds[roomId]

src/frontend/src/stores/userChoices.ts

@@ -1,4 +1,6 @@
 import { proxy, subscribe } from 'valtio'
+import { initializeAccessTokenFromFragment } from '@/features/auth/api/exchangeAccessToken'
+import { getAccessToken } from '@/stores/accessToken'
 import {
   ProcessorConfig,
   ProcessorType,
@@ -48,10 +50,19 @@ if (userChoicesStore.processorConfig?.type === ProcessorType.VIRTUAL) {
     // we restore clear the processor config to avoid displaying a black screen.
     userChoicesStore.processorConfig = undefined
   } else if (userChoicesStore.processorConfig.fileId) {
+    // Embedded (token) mode: this module loads before the transit code
+    // exchange has settled - wait for it, and carry the Bearer header,
+    // otherwise the check below would wrongly clear the config.
+    await initializeAccessTokenFromFragment()
+    const accessToken = getAccessToken()
+
     // Checking if the image is still available / accessible
     await fetch(userChoicesStore.processorConfig.imagePath, {
       // We bypass the cache to ensure we have access
       cache: 'reload',
+      ...(accessToken && {
+        headers: { Authorization: `Bearer ${accessToken}` },
+      }),
     })
       .then((response) => {
         // if we cannot fetch the image (likely a 401 from the backend because