Classy Login (OpenID Connect SSO)
GoFundMe Pro's single sign-on service, implemented against OpenID Connect, letting third-party apps register and log people in with their Classy/GoFundMe Pro account. Authorization endpoint at login.classy.org/authorize, token endpoint at api.classy.org/oauth2/auth, userinfo at api.classy.org/2.0/me. Supports redirect, popup and iframe flows via a JavaScript SDK.