post https://api-sandbox.astra.finance/v1/oauth/token
You can place your application's client_id into the username field, and your client_secret into the password form field of the Authentication section of this documentation 👉.
Use this endpoint to both initially Authorize a User, and also to Refresh Authorization for a user.
In the Form Data below, Option 1 is for the initial action to Authorize a User. Option 2 is for the action of using the refresh_token to generate a new access_token.