Hi 

I am making API requests, and I know that you're using basic auth instead of Token. Is there a redirect/callback method that one can use to store User Credentials on the first-time login, or is the best way to deal with this to save these credentials in our database? So, we do not know who our users are when they log in to our system. We don't know whether they are going to select Sage, QuickBooks, or Xero. Normally, with the other accounting systems, there's a redirect/callback function. How do you guys cater to that?