Fix redirect_uri_mismatch Error in OAuth: Step-by-Step Guide

The “redirect_uri_mismatch” error is a common issue encountered during OAuth 2 authorization. It occurs when the redirect URI specified in your application’s authentication request does not match the one registered with the OAuth provider. This mismatch prevents users from logging in and completing authentication.

What Causes “redirect_uri_mismatch” Error?

The error typically happens due to one of the following reasons:

1. Incorrect Redirect URI in Your Request – The redirect URI in your application does not exactly match the one configured in the OAuth provider.
2. Missing or Misconfigured Redirect URIs in the OAuth Provider – You haven’t added the correct URI in the OAuth settings.
3. Protocol Mismatch – Your application is using http:// instead of https://.
4. Trailing Slash Issues – Some OAuth providers treat https://yourdomain.com/callback and https://yourdomain.com/callback/ as different URIs.
5. Using localhost for Testing – If you’re running your application locally, your redirect URI must be explicitly added (http://localhost:3000/callback).
6. Wrong Environment Configuration – Your development and production environments may have different redirect URIs.

How to Fix the “redirect_uri_mismatch” Error?

Follow these steps to troubleshoot and resolve the issue:

1. Verify the Redirect URI in Your Application

Check the URL your application sends during the OAuth request. It should match exactly with the one registered in your OAuth provider’s settings.

• Open your code where the OAuth request is initiated.
• Locate the redirect_uri parameter in the request.
• Ensure the value is correct and matches the OAuth provider’s configuration.

Example:

redirect_uri = "https://yourdomain.com/auth/callback"

2. Update the OAuth Provider Settings

Each OAuth provider (Google, Facebook, GitHub, etc.) requires you to register authorized redirect URIs.

For Google OAuth (Google Cloud Console):

1. Go to Google Cloud Console (https://console.cloud.google.com/).
2. Navigate to APIs & Services > Credentials.
3. Click on your OAuth 2.0 Client ID.
4. Under Authorized redirect URIs, add the correct redirect URI used in your application.
5. Click Save and wait a few minutes for changes to take effect.

3. Ensure the Correct Protocol (http vs. https)

• If your site runs over HTTPS, ensure your redirect URI uses https:// instead of http://.
• OAuth providers often block non-secure (http) redirect URIs in production.

Example of incorrect and correct URIs:

• http://yourdomain.com/auth/callback (Incorrect)
• https://yourdomain.com/auth/callback (Correct)

For local development, ensure you explicitly add http://localhost:3000/callback to your OAuth provider’s settings.

4. Check for Trailing Slash Issues

Some OAuth providers treat URIs with and without a trailing slash as different.

Example:

• https://yourdomain.com/auth/callback/ (Incorrect)
• https://yourdomain.com/auth/callback (Correct)

Ensure that the registered redirect URI matches exactly what your application is sending.

5. Match Development and Production Redirect URIs

If you have separate environments for development and production, ensure both are configured correctly.

Example:

• Development: http://localhost:3000/auth/callback
• Production: https://yourdomain.com/auth/callback

Both must be added to your OAuth provider.

6. Allow Time for Changes to Propagate

If you recently updated your OAuth settings, wait a few minutes for the changes to take effect before testing again.

Final Thoughts

The “redirect_uri_mismatch” error is a common but fixable issue in OAuth authentication. The key to resolving it is to ensure that the redirect URI in your application exactly matches the one registered with your OAuth provider.

By following the steps above, you should be able to troubleshoot and fix the error quickly.

If you’re still experiencing issues, comment down for further assistance.