I'm wondering if there exist a set of good practices for building the customer/accounts/payments framework around a SaaS product. I imagine they tend to be similar from product to product. However, I've not personally run across them.
Regards, Paul
Handle payments using stripe.com, it can handle subscriptions as well. You can store your customers stripe id and pull up their invoices, next billing date, last 4 of their cc, etc via the stripe api to show in their profile. And setup stripe api hooks to keep track of any failed billings (show a reminder when they log in) and other events that happen on the stripe side of things.
There are all kinds of smart ways to set things up with regard to signups, failed billings, tracking user logins/engagement. And there are always new ideas/best practices evolving.
For transactional emails I recommend mandrill.com.
Good luck in 2015.
I'm sure there is something out there, I just haven't come across it yet!