(backend) wip introduce a token exchange endpoint

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

@@ -580,3 +580,25 @@ 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

@@ -73,3 +73,14 @@ 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,

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/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_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_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_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",
@@ -953,6 +959,61 @@ 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 +1311,10 @@ 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/backend/pyproject.toml

@@ -40,7 +40,7 @@ dependencies = [
     "django-storages[s3]==1.14.6",
     "django-timezone-field>=5.1",
     "django-pydantic-field==0.5.4",
-    "django==5.2.16",
+    "django==5.2.14",
     "djangorestframework==3.17.1",
     "drf_spectacular==0.29.0",
     "dockerflow==2026.3.4",

src/backend/uv.lock

@@ -586,16 +586,16 @@ wheels = [
 
 [[package]]
 name = "django"
-version = "5.2.16"
+version = "5.2.14"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "asgiref" },
     { name = "sqlparse" },
     { name = "tzdata", marker = "sys_platform == 'win32'" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/a9/26/889449d521ae508b26de715954faecd8bcf3f740affb81b2d146a83b42a5/django-5.2.16.tar.gz", hash = "sha256:59ea02020c3136fce14bef0bbece21a10a4febef5eed1c51c22ae468efa22200", size = 10890894, upload-time = "2026-07-07T13:52:17.005Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/65/95/95f7faa0950867afaa0bef2460c6263afd6a2c78cc9434046ed28160b015/django-5.2.14.tar.gz", hash = "sha256:58a63ba841662e5c686b57ba1fec52ddd68c0b93bd96ac3029d55728f00bf8a2", size = 10895118, upload-time = "2026-05-05T13:57:31.104Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/4e/13/1e5e3e4c15dcecb04281b3cb2a46a4670e1cef131068e202f6040df19224/django-5.2.16-py3-none-any.whl", hash = "sha256:04f354bf9d807a86ad1a8392fe3808d362358a8eafc322848e0e43e59b24371d", size = 8311943, upload-time = "2026-07-07T13:52:11.223Z" },
+    { url = "https://files.pythonhosted.org/packages/14/44/f172870cf87aa25afef48fb72adba89ee8b77fcab6f3b23d240b923f1528/django-5.2.14-py3-none-any.whl", hash = "sha256:6f712143bd3064310d1f50fac859c3e9a274bdcfc9595339853be7779297fc76", size = 8311320, upload-time = "2026-05-05T13:57:25.795Z" },
 ]
 
 [[package]]
@@ -1260,7 +1260,7 @@ requires-dist = [
     { name = "brotli", specifier = "==1.2.0" },
     { name = "celery", extras = ["redis"], specifier = "==5.6.3" },
     { name = "dj-database-url", specifier = "==3.1.2" },
-    { name = "django", specifier = "==5.2.16" },
+    { name = "django", specifier = "==5.2.14" },
     { name = "django-configurations", specifier = "==2.5.1" },
     { name = "django-cors-headers", specifier = "==4.9.0" },
     { name = "django-countries", specifier = "==9.0.0" },

src/frontend/src/components/Avatar.tsx

@@ -59,10 +59,9 @@ export const Avatar = React.memo(
           <text
             x="50"
             y="50"
-            dy="-0.08em"
             textAnchor="middle"
             dominantBaseline="central"
-            fontSize="52"
+            fontSize={initials.length > 1 ? 48 : 52}
             fontWeight="500"
             fill="currentColor"
           >