Resharing from Nov 2022: I put together a basic proof of concept for using existing #Mastodon installations as SSO for #Matrix, using #Synapse. Here's what the authentication and authorization flow for that looks like!

While Mastodon doesn't support #OpenlDConnect, #OIDC is just #OpenlD on top of #OAuth2.0. If your app allows configuring all URLS for your ldP you can use nearly any OAuth2.0 provider.

Avatars currently aren't supported via this (| added one) but can be!

https://blimps.xyz/@ceralor/109400447635352242