Sign in With Apple is OpenID, which is an open standard. See https://openid.net/2019/09/30/apple-successfully-implements-openid-connect-with-sign-in-with-apple/

Sign in With Apple is OpenID, which is an open standard. See https://openid.net/2019/09/30/apple-successfully-implements-openid-connect-with-sign-in-with-apple/ https://openid.net/2019/09/30/apple-successfully-implements-... A fellow comment downthread encapsulates the benefit of this change perfectly: “There was some app I downloaded last year which only had facebook or google sign on. You couldn't register with an email. I ended up deleting the app.”