OAuth 2.0 Refresh Token Flow
Flow where a client silently obtains a new access token by presenting its refresh token to the authorization server, instead of prompting the user to sign in again.
Access tokens are short-lived by design. When one expires, the client doesn't need to send the user through another login: if it holds a refresh token, it can exchange it at the authorization server's token endpoint for a new access token. The user is not involved at any point.
Authorization servers may rotate the refresh token on every use, returning a new one and invalidating the old one. Clients should always store the latest refresh token they receive. Confidential clients must also authenticate when calling the token endpoint.