Supabase Auth: Redirect URLs, Site URL, Cookies, and Sessions Authentication often breaks only after deployment because localhost redirect assumptions remain in the Auth project. Production Auth configuration must know the canonical web URL and every intentional callback.
Sign in → Supabase Auth → Allowed redirect → /auth/confirm → Session cookie
Production URL configuration • Site URL: https://app.taskflow.example.com
• Add exact production redirect paths used by confirmation/OAuth/reset flows.
• Use preview wildcards only for preview environments and keep production redirects exact where possible.
• Verify email templates use the intended redirect value when redirectTo is used.
Session checks • Cookies must be Secure over HTTPS.
• Cross-site/cross-origin behavior must match the Phase 16-18 authentication model.
• A successful web login does not replace NestJS bearer-token verification; the API still validates identity independently. A correct production domain is part of authentication correctness. Redirect allowlists are security configuration, not cosmetic routing.
Source: Supabase Auth Redirect URLs and URL Configuration guidance.
Authentication answers who the request represents. Treating decoded or client-supplied identity as trusted is a security boundary failure.
Restate the goal of “Supabase Auth Redirects Cookies and Sessions” as one observable behavior. Write the success signal before touching code.
Trace the boundary map: credentials/session → token → verification → trusted identity → protected operation. Mark the one boundary this lesson changes.
Inspect the current repository state and record the exact files, route, table, or runtime involved. Avoid creating an abstraction before you can name the existing owner.
Implement the smallest vertical slice. Add one coherent change, run the narrowest verification command, and read the output before continuing.
Connect the slice to TaskFlow’s phase artifact: Staging and production deployment runbooks with release identity, environment matrix, smoke tests, and rollback procedure.. Verify behavior from the outside as a user or API client would.
Create one controlled failure that is safe to reproduce. Predict the symptom first, capture evidence, locate the earliest broken boundary, then fix only that cause.
Close the reference and rebuild or explain the core change from memory. Record what you would monitor or test before trusting the same change in production.
const token = readBearerToken(request);
const claims = await verifier.verify(token);
request.user = {
id: claims.sub,
email: claims.email,
};Do not copy this as a finished answer. Predict what each boundary does, type the smallest useful slice, run it, then compare the result with your prediction.
Inspect whether a token exists, whether it is expired, which issuer/audience signed it, and what the API verifier expects.
Trust only verified server claims; never repair identity by accepting a client-sent user id.
Without copying the final source, create a second small scenario that applies “Supabase Auth Redirects Cookies and Sessions” to a different TaskFlow resource or input. Write the acceptance criteria first, implement it, and provide the evidence that each criterion is satisfied.
Run a smoke-test checklist and practice rollback of code while reasoning about whether the database migration is reversible.
Use the smallest change that demonstrates this lesson. Stop after it works and capture evidence.Secrets copied into source or image
Predict the symptom before causing the failure. Then locate the earliest boundary where reality diverges from expectation.Why does this responsibility live here, what input does it trust, what output proves success, and what would go wrong if another layer owned it?
If your explanation is vague, repeat the boundary trace before moving on.Close the reference. Reproduce the core idea from memory or explain the exact request/data flow aloud. Then check your diff or notes for accidental shortcuts that bypass validation, authorization, error handling, or verification earned in earlier phases.