ERR-435/stack trace

ERR-435

Windsurf app auth not working — fix auth after deploy

Windsurf app auth not working — fix auth after deploy

Last updated 17 April 2026 · 7 min read · By Hyder Shah

Emergency triage — $299 Free diagnostic

Direct answer

Windsurf generates code that runs locally. When you deploy, authentication requires explicit production configuration: OAuth redirect URLs must be updated, session secrets must be environment variables, and database access control (RLS) must be explicitly enabled. Four fixes cover 90% of Windsurf auth failures.

Quick fix for Windsurf app auth not working —

Start here

Fix 1 — Update OAuth redirect URLs

In Supabase Auth settings or your OAuth provider: add your production URL to authorised redirect URLs. If using Vercel: both yourapp.vercel.appand your custom domain need to be listed. Test by clicking the OAuth button on the production URL — any redirect_uri_mismatch error points to this step.

Deeper fixes when the quick fix fails

02
Fix 2 — Add session configuration to production env
Any SESSION_SECRET, NEXTAUTH_SECRET, or similar must be set as environment variables in your deployment platform — not hardcoded. Generate a secure value:
```
openssl rand -base64 32
```
Paste the output into Vercel → Project → Settings → Environment Variables (or Railway’s Variables tab) and redeploy.
03
Fix 3 — Enable Supabase RLS
Cascade generates Supabase queries but doesn’t always enable RLS. Check each table in Supabase Dashboard → Table Editor. Enable RLS and add SELECT/INSERT/UPDATE/DELETE policies filtered by auth.uid() = user_id. Without this, any authenticated user can read every other user’s rows.
04
Fix 4 — Verify auth in production incognito
Open your production URL in an incognito window. Test: sign up → receive confirmation email → confirm → sign in → reload page (session should persist) → sign out. Any failure indicates a specific gap to fix. Repeat with a second account and verify no cross-user data leakage.

After it works

Do a final audit of every environment variable: production should have the same set as .env.local but with production values (live Stripe keys, production Supabase URL, your real domain in NEXTAUTH_URL). Stale or missing env vars are the #1 cause of “worked locally, broken live”.

Why AI-built apps hit Windsurf app auth not working —

Windsurf Cascade generates complete auth flows based on your prompts. But Cascade doesn’t know your production deployment URL, your database’s RLS requirements, or your OAuth app’s allowed origins. These require manual configuration after code generation.

Locally everything works because .env.local has the right secrets, localhost:3000 is whitelisted, and your single-user testing never exposes missing database policies. Deploy to Vercel or Railway and all three gaps surface at once.

“Windsurf built a great auth system but it all breaks in production.”

Reddit — r/windsurf_ai

Diagnose Windsurf app auth not working — by failure mode

Test each layer in order; the first failure is usually the root cause of the rest.

Symptom	Cause	Fix
OAuth fails: 'redirect_uri_mismatch'	Production URL not in OAuth provider's allowed list	Fix 1
Session drops on every page reload	SESSION_SECRET / NEXTAUTH_SECRET missing in prod env	Fix 2
User A can see User B's data	Supabase RLS not enabled by Cascade	Fix 3
Works on localhost but breaks on production URL	Cookies/callbacks behave differently in prod	Fix 4

Related errors we fix

Still stuck with Windsurf app auth not working —?

Emergency triage · $299 · 48h turnaround

We restore service and write the root-cause report.

If auth works on your laptop but breaks the moment you deploy, we fix the full chain:

→Your Windsurf-built app login works locally but fails live
→OAuth errors with redirect_uri_mismatch on production
→Users are being logged out on every refresh
→You're not sure which Supabase tables have RLS enabled

start the triage →

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Emergency Triage

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Auth end-to-end, verified with a 2-account test

Auth, Database & Integrations

From $799

Auth + RLS + OAuth + email wired end-to-end

Deployment & Launch

From $1,999

Production-ready: auth, deploy, monitoring, SSL

Windsurf app auth not working — questions

Why does my Windsurf app auth work locally but break in production?+

Three reasons, in order: (1) OAuth provider only whitelists localhost:3000, (2) session secrets only exist in .env.local and weren't added to your deploy platform's environment variables, (3) Supabase tables have RLS disabled and single-user local testing never exposed the problem. Fix all three and production auth starts working.

What's Cascade and why does it matter for auth?+

Cascade is Windsurf's in-editor AI that writes and edits code across your project. It generates complete auth flows — sign-up forms, OAuth buttons, session middleware — but operates without knowledge of your production URL, OAuth app settings, or database policies. Those require manual configuration after Cascade finishes.

How do I know if Cascade enabled Supabase RLS on my tables?+

Supabase Dashboard → Table Editor. Each table shows an RLS indicator. If any table says 'RLS disabled', every authenticated user can read every row via the Supabase JS client. Cascade usually doesn't enable RLS unless you explicitly prompted it to — audit every table and enable RLS with per-user policies.

My .env.local has everything but production is still broken. What's missing?+

You have to copy every .env.local variable into your deploy platform manually. Vercel: Project → Settings → Environment Variables. Railway: Variables tab. Common miss: NEXT_PUBLIC_ prefix for client-side vars (without it, the variable is server-only), or NEXTAUTH_URL set to localhost:3000 instead of your production domain.

Should I use Supabase, Clerk, or NextAuth with a Windsurf app?+

Cascade handles all three well if you specify in the prompt. Supabase is the best fit if you also need a database (you get auth + Postgres + RLS in one service). Clerk is the best fit if you want a polished pre-built UI. NextAuth if you want maximum flexibility. For most Windsurf rescues, we migrate to Supabase.

Can you fix all four of these for me?+

Yes. Our $299 Emergency Triage covers all four fixes plus a verified two-account production test in an incognito window. 48-hour turnaround. For a production-hardened setup with RLS audit, monitoring, and custom domain, our Deployment & Launch package starts at $1,999.

Next step

Ship the fix. Keep the fix.

Emergency Triage restores service in 48 hours. Break the Fix Loop rebuilds CI so this error cannot ship again.

Emergency triage — $299 Free diagnostic

About the author

Hyder Shah leads Afterbuild Labs, shipping production rescues for apps built in Lovable, Bolt.new, Cursor, Replit, v0, and Base44. our rescue methodology.

Windsurf app auth not working — experts

If this problem keeps coming back, you probably need ongoing expertise in the underlying stack.