# Authentication through an OpenID Connect provider
## Overview
Dex is able to use another OpenID Connect provider as an authentication source. When logging in, dex will redirect to the upstream provider and perform the necessary OAuth2 flows to determine the end users email, username, etc. More details on the OpenID Connect protocol can be found in [_An overview of OpenID Connect_][oidc-doc].
Prominent examples of OpenID Connect providers include Google Accounts, Salesforce, and Azure AD v2 ([not v1][azure-ad-v1]).
When using refresh tokens, changes to the upstream claims aren't propegated to the id_token returned by dex. If a user's email changes, the "email" claim returned by dex won't change unless the user logs in again. Progress for this is tracked in [issue #863][issue-863].