Monzo OAuth “Whoops!” Error — Only Developer Account Can Connect

Developers
1

Hi Monzo Developer Support / Community,

I’m integrating Monzo OAuth into my app using a live client. Everything works perfectly when I go through the OAuth flow with my developer account — I receive the magic link, log in, and successfully fetch /balance and /transactions.

However, when other users (non-developers) try to connect, they get a “Whoops! There was a problem” error after clicking the magic link in their email. No access tokens are returned, and they’re unable to connect their bank account.

Key points:

  • I’m using a live Monzo client, not the Playground
  • My redirect URI is properly set and working:https://7dc1b4eb-xxxxxx.replit.dev/monzo/callback
  • Only my email (as app creator) works; all others fail
  • No error messages in logs beyond the failed redirect

Has anyone experienced this?

Is this a limitation of live apps still being treated like dev mode?

What steps do I need to take to enable multi-user access?

Thanks in advance for any guidance — I’d really appreciate help unblocking this.

1 Like
2

The Monzo Developer API is not suitable for building public applications.
You may only connect to your own account or those of a small set of users you explicitly allow.

IIRC Applications designed for public consumption have to use Open Banking APIs (and clear the higher barrier to entry that entails) instead of using the specific Monzo API. There was intent to open the API up more “at some point [in 2018]” but never happened