I’m getting redirect_uri_mismatch on Google login

redirect_uri_mismatch means the redirect URI your app is sending to Google does not exactly match one of the URIs configured in your Google Cloud OAuth client.

What to check

1) Compare the exact redirect URI

Look at the URI your app sends in the OAuth request, for example:

• http://localhost:3000/api/auth/callback/google
• https://example.com/auth/google/callback

It must match exactly in Google Cloud Console:

• same http vs https
• same domain
• same port
• same path
• trailing slash matters
• no extra query params

2) Add it in Google Cloud Console

Go to:

Google Cloud Console → APIs & Services → Credentials → OAuth 2.0 Client IDs

Then under your OAuth client, add the redirect URI in:

Authorized redirect URIs

3) Make sure you’re editing the right OAuth client

If you have multiple OAuth client IDs, confirm the app is using the same client ID that you updated.

4) Check your app/framework config

Common framework defaults:

• NextAuth/Auth.js:
  http://localhost:3000/api/auth/callback/google
• Passport.js:
  depends on your callback route
• Firebase/Auth UI:
  often uses project-specific callback URLs

5) Watch out for environment differences

If it works locally but not in production, add both:

• local callback URL
• production callback URL

Example

If your app uses:

http://localhost:3000/auth/google/callback

then Google Cloud must contain exactly that URI, not:

http://localhost:3000/auth/google/callback/
https://localhost:3000/auth/google/callback

If you want, I can help you fix it quickly

Send me:

1. the redirect URI your app is using
2. the framework/library you’re using
3. the redirect URIs currently listed in Google Cloud

and I’ll tell you exactly what to change.