Simon Willison’s Weblog

14th October 2024 - Link Blog

Grant Negotiation and Authorization Protocol (GNAP) (via) RFC 9635 was published a few days ago. GNAP is effectively OAuth 3 - it's a newly standardized design for a protocol for delegating authorization so an application can access data on your behalf.

The most interesting difference between GNAP and OAuth 2 is that GNAP no longer requires clients to be registered in advance. With OAuth the client_id and client_secret need to be configured for each application, which means applications need to register with their targets - creating a new application on GitHub or Twitter before implementing the authorization flow, for example.

With GNAP that's no longer necessary. The protocol allows a client to provide a key as part of the first request to the server which is then used in later stages of the interaction.

GNAP has been brewing for a long time. The IETF working group was chartered in 2020, and two of the example implementations (gnap-client-js and oauth-xyz-nodejs) last saw commits more than four years ago.