Independent and unofficial. This Python project is inspired by Better Auth and is not affiliated with, maintained by, endorsed by, or sponsored by the Better Auth project or its maintainers.

BETTER-AUTH.

no_callback_url

The callback URL was not found in the request.

What is it?

This error occurs during the OAuth flow when the request reaches your /api/auth/callback endpoint but the state data does not contain a callback URL. Better Auth stores metadata in state when the flow starts, including where to redirect after a successful sign-in/link. If that URL is missing at callback time, we cannot safely continue.

Common Causes

  • The OAuth flow was not started via Better Auth APIs, so the state payload never included a callback URL.
  • A reverse proxy, CDN, or middleware altered the flow, causing the app to read a different or empty state.

How to resolve

Start the flow through Better Auth

  • Always initiate OAuth using Better Auth's built-in methods so state is generated with the needed fields.
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What is it?
Common Causes
How to resolve
Start the flow through Better Auth