The authorization code grant type is designed for confidential clients (e.g. websites with a server back end) that can keep a secret. This type can request for offline_access scope (i.e. to request for refresh token).

  1. Use the authorization end point to request the authorization code with the following query parameters:

    response_type = code 
    client_id = the client unique code
    redirect_uri = redirection URL.
    state = (Optional) value to echo to us.
    scope = (Optional) what permision wanted. If not specified, default permission will be given.
    response_mode = (Optional) query

    A login form will be displayed if not yet filled-up before.

    Expected Response

    The redirect_uri with the following query parameters:

    code = The authorization code
    state = state value if given.
  2. Use the token end point to do post request for the access token with the following headers:

    Content-Type = application/x-www-form-urlencoded
    Authorization = Basic <CREDENTIAL>

    And with the following parameters:

    grant_type = authorization_code.
    code = The authorization code from step 1.
    redirect_uri = The used from step 1.

    Expected Response

    Header

    Content-Type: application/json
    
    {
    "access_token" : <ACCESS_TOKEN>,
    "token_type" : "Bearer",
    "expires_in" : 3600,
    "scope" : <The scope allowed by the server>
    }
  3. Call the API with the authorization header like the following syntax:

    Bearer <ACCESS_TOKEN>

Sample implementation can be found here.