> Just look at how the big FANG companies managed to adopt OpenID and yet made it so that it can't be used to authenticate users between them. They never liked

> Just look at how the big FANG companies managed to adopt OpenID and yet made it so that it can't be used to authenticate users between them. They never liked identity federation because it would mean not controlling the user's identity completely. Google loves identity standards as long as Google is the one and only party doing the authenticating. Same with Microsoft. Apple for sure is not going to let anyone do anything that matters on their platforms. actually OpenID Connect 1.0 - the thing that most companies use (like google, apple, microsoft) actually does not yet support Federation. OpenID Connect is basically a little bit more than OAuth2 (which was never about Federation) Of course there is a draft spec about federation: https://openid.net/specs/openid-connect-federation-1_0.html https://openid.net/specs/openid-connect-federation-1_0.html (unfortunatly only microsoft is included and not google), there is also: https://openid.net/specs/openid-connect-self-issued-v2-1_0.html https://openid.net/specs/openid-connect-self-issued-v2-1_0.h... (also only a draft one...) but I'm pretty sure that both will probably allow the usage of federation at one point - at least for Commercial entities. Because Google Cloud Identity actually supports SCIM 2.0 and upstream OpenID Connect IdP's or SAML2 (https://cloud.google.com/architecture/identity/keycloak-single-sign-on?hl=de https://cloud.google.com/architecture/identity/keycloak-sing...). the original OpenID Authentication spec was about federatation, but barley nobody implemented it. (I can only think about StackOverflow (which dropped it in 2018) and something at RedHat/Fedora - can't remember?)