Refreshing access tokens

A client app may need to exchange refresh tokens for access tokens after the old access tokens have expired or to get access to a new resource for the first time. To do so, it can send a request to the token endpoint.

Note: The Authorization Server issues refresh tokens only via the authorization code grant flow.

Token endpoint

To exchange a refresh token for an access token, a client app should send a request to the following endpoint:

Authorization: Basic <client-id>,<client-secret> 
Content-Type: application/x-www-form-urlencoded 

Note the parameters in the request:
The grant type must be set to refresh_token.
The refresh token previously issued to the client.

The response to the refresh token grant is the same as when issuing an access token.