Authentication is the gatekeeper — when it breaks, nothing works. Whether it is NextAuth, auth.js, JWT sessions, OAuth providers, or password-based auth, we diagnose and fix it. Working code via GitHub PR within 48 hours.
These are the authentication errors we fix most often.
We find the actual cause — not just patch the error message.
Session strategy (JWT vs database sessions) is misconfigured for the app architecture, causing tokens to be rejected.
Redirect URIs in OAuth provider console do not match the callback URL in the app — a common mismatch after domain changes.
JWT signing secrets are set differently in production vs development, causing token verification to fail.
Next.js middleware authentication checks use incorrect path patterns, allowing or blocking access incorrectly.
Cross-Origin Resource Sharing settings block legitimate auth requests from the frontend.
Four steps to secure, working auth.
Link your GitHub repository. We support public and private repos — you control access.
We trace the auth flow end-to-end to find where sessions, tokens, or redirects break.
Receive a transparent quote. You approve before any code changes are made.
Working auth with proper security — delivered via GitHub PR within 48 hours.
NextAuth, auth.js, Supabase, Firebase, Clerk, and custom auth systems.