Cross-subdomain session spike

One question: does the platform_session cookie survive a fetch from this origin to the API on another subdomain, and can this page read the response? Throwaway diagnostic — delete it once the real frontend exists.

Environment

This page's origin
API base URL
Registrable domain
Transport
document.cookie

1 · Log in

POST /v1/auth/login with credentials: 'include'. This request carries Content-Type: application/json, so the browser sends a CORS preflight first — a misconfigured origin fails here before any cookie is issued.

2 · Check the session

GET /v1/auth/me with credentials: 'include'. Runs automatically after a successful login. This is the request that proves — or disproves — that the browser stored the cookie and attached it to a cross-subdomain call.

3 · Re-check after a hard reload

The interesting failure is a cookie that is set but not sent back on a later request. Log in above, then hard-reload (Ctrl/Cmd + Shift + R) and press this button. It repeats the /v1/auth/me call using nothing but what the browser persisted across the reload.

4 · Log out

POST /v1/auth/logout, sent with no body and no custom headers so it stays a simple request and skips the preflight. Revokes the session and clears the cookie; 204, no body. A later /v1/auth/me should then say invalid or expired session, not missing credentials — that difference is what tells cookie transport apart from a dead session.

Request log

Nothing sent yet.

Response headers are not shown: auth sets no Access-Control-Expose-Headers, so a cross-origin page cannot read X-Request-Id. Find it in the gateway log instead. Where a request produced no HTTP response at all, the browser's real reason is only in DevTools → Console.