To call our API you'll need a token. You can get this token in two steps. To begin the flow, you'll need to get the user's authorization. You do this by redirecting the user to the authorize URL:

You need to add the following fields to the URL as query parameters:

client_idThis is your unique client ID, you'll get this when you become an Unless partner.
redirect_uriThe URL you need the customer to redirect back to after authenticating. This needs to be whitelisted in our system.
scopeAvailable scopes are:
response_typeThe response type should be 'code'.
audienceThe audience should be ''

The user will see a login prompt and a consent dialog. After a successful login and consent the user will be redirected to the 'redirect_url'. If all goes well, you'll receive an HTTP 302 response. The authorization code is included at the end of the URL:

HTTP/1.1 302 Found
Location: https://YOUR_APP/callback?code=AUTHORIZATION_CODE