From 5ecf746b6451ee77718e623df1128eac161ab0f8 Mon Sep 17 00:00:00 2001
From: Nolann Biron <biron.nolann@gmail.com>
Date: Thu, 10 Sep 2026 12:25:18 +0200
Subject: [PATCH] Request insights and visitor endpoints relative to the served
 origin

---
 .changeset/relative-insights-visitor-urls.md  |  5 +++++
 .../components/SpaceLayout/SpaceLayout.tsx    | 18 +++++++--------
 packages/gitbook/tests/insights.test.ts       | 22 +++++++++++++++++++
 3 files changed, 36 insertions(+), 9 deletions(-)
 create mode 100644 .changeset/relative-insights-visitor-urls.md
 create mode 100644 packages/gitbook/tests/insights.test.ts

diff --git a/.changeset/relative-insights-visitor-urls.md b/.changeset/relative-insights-visitor-urls.md
new file mode 100644
index 000000000..fe848a113
--- /dev/null
+++ b/.changeset/relative-insights-visitor-urls.md
@@ -0,0 +1,5 @@
+---
+"gitbook": patch
+---
+
+Fix analytics and adaptive content silently breaking on sites served from a different host than the one configured (apex vs www, domain alias, CDN). The insights and visitor-claims endpoints are now requested relative to the page's own origin instead of the configured host, which a prerendered page cannot know.
diff --git a/packages/gitbook/src/components/SpaceLayout/SpaceLayout.tsx b/packages/gitbook/src/components/SpaceLayout/SpaceLayout.tsx
index df6b60f32..0a1f6a30d 100644
--- a/packages/gitbook/src/components/SpaceLayout/SpaceLayout.tsx
+++ b/packages/gitbook/src/components/SpaceLayout/SpaceLayout.tsx
@@ -58,15 +58,15 @@ export function SpaceLayoutServerContext(props: SpaceLayoutProps) {
             ? context.linker.toPathInSite('~gitbook/auth/login')
             : null;
 
-    const eventUrl = new URL(
-        context.linker.toAbsoluteURL(context.linker.toPathInSite('/~gitbook/__evt'))
-    );
-    eventUrl.searchParams.set('o', context.organizationId);
-    eventUrl.searchParams.set('s', context.site.id);
+    // Kept relative: a prerendered page has no request to read the host from, so an absolute URL
+    // pins the configured host and turns these fetches cross-origin when it differs (apex vs www).
+    const eventParams = new URLSearchParams({
+        o: context.organizationId,
+        s: context.site.id,
+    });
+    const eventUrl = `${context.linker.toPathInSite('/~gitbook/__evt')}?${eventParams}`;
 
-    const getVisitorClaimsUrl = context.linker.toAbsoluteURL(
-        context.linker.toPathInSite('/~gitbook/visitor')
-    );
+    const getVisitorClaimsUrl = context.linker.toPathInSite('/~gitbook/visitor');
 
     return (
         <SpaceLayoutContextProvider
@@ -92,7 +92,7 @@ export function SpaceLayoutServerContext(props: SpaceLayoutProps) {
                         appURL={GITBOOK_APP_URL}
                         visitorCookieTrackingEnabled={customization.insights?.trackingCookie}
                     >
-                        <InsightsProvider enabled={withTracking} eventUrl={eventUrl.toString()}>
+                        <InsightsProvider enabled={withTracking} eventUrl={eventUrl}>
                             <AIChatProvider
                                 renderMessageOptions={aiChatRenderMessageOptions}
                                 withPageFeedback={customization.feedback.enabled}
diff --git a/packages/gitbook/tests/insights.test.ts b/packages/gitbook/tests/insights.test.ts
new file mode 100644
index 000000000..d98598c2c
--- /dev/null
+++ b/packages/gitbook/tests/insights.test.ts
@@ -0,0 +1,22 @@
+import { describe, expect, it } from 'bun:test';
+
+import { getContentTestURL } from './utils';
+
+describe('Insights', () => {
+    // The harness serves the site from BASE_URL while it is configured on gitbook.gitbook.io,
+    // reproducing the split (apex vs www, alias, CDN) that turns an absolute URL cross-origin.
+    const TEST_URL = getContentTestURL('https://gitbook.gitbook.io/test-gitbook-open');
+
+    it.each(['__evt', 'visitor'])(
+        'should reference ~gitbook/%s relative to the served origin',
+        async (endpoint) => {
+            const response = await fetch(TEST_URL);
+            expect(response.status).toBe(200);
+
+            const html = await response.text();
+
+            expect(html).toContain(`~gitbook/${endpoint}`);
+            expect(html).not.toMatch(new RegExp(`https?://[^"'\\\\\\s]*~gitbook/${endpoint}`));
+        }
+    );
+});