Compatible Relying Parties

[erlend-sh]

Relying Parties is OIDC-speak for web apps.

Requirements.

• OIDC
  • PKCE – Proof Key for Code Exchange by OAuth Public Clients

We are testing for compatibility with the following RP apps:

IndieWeb

• [x] Forgejo
• [x] Linkding
• [x] Miniflux
• [ ] OpenGist, pending https://github.com/thomiceli/opengist/issues/227
• [x] Linkblocks, pending https://github.com/raffomania/linkblocks/pull/51
• [ ] https://github.com/neodb-social/neodb
• [ ] Shiori, pending OIDC support
• [ ] Mattermost
• [ ] Zulip
• [ ] Matrix (Conduit), pending OIDC support
• [ ] Memos

Fediverse

• [x] Mastodon, https://github.com/mastodon/mastodon/pull/31131
• [x] ATproto, https://github.com/bluesky-social/atproto/pull/2482
• [ ] Kitsune
• [ ] https://github.com/activitypods/activitypods/issues/121
• [ ] Fedify (??)
• [ ] GoToSocial, pending https://github.com/superseriousbusiness/gotosocial/issues/2225
• [ ] Lemmy, https://github.com/LemmyNet/lemmy/pull/4881
• [ ] https://newsmast.org/

Alt-web

• https://kinopio.club/
• Supabase
• Glitch
• Val.town
• DEV.to
• GitLab
• Ghost
• https://www.are.na/
• https://neocities.org/
• Obsidian
• Wikipedia
• Proton
• Memos
• Tailscale
• Polar - https://github.com/polarsource/polar/issues/3728

[zicklag]

Just tested Gotosocial. Needs PKCE support like OpenGist: https://github.com/superseriousbusiness/gotosocial/issues/2225.

[ThisIsMissEm]

Do keep in mind that Mastodon does not implement OIDC for API access, but does for SSO; That is, Mastodon is always an OAuth 2 provider / authorization server, however it can be configured to do SSO via OIDC

That is to say, https://github.com/mastodon/mastodon/pull/30329 is probably entirely unrelated to what you're doing here, which seems to be SSO.

[ThisIsMissEm]

So what you'd want for Mastodon SSO to support PKCE is the PKCE configuration options passed to config.omniauth :openid_connect, oidc_options in https://github.com/mastodon/mastodon/blob/e56fb9e4890435ef89b56ef5d1b9a8d0d46ab938/config/initializers/3_omniauth.rb — currently it does not include those options: https://github.com/omniauth/omniauth_openid_connect?tab=readme-ov-file#options-overview