What billing systems use saas services?

Question

Billing systems

Good afternoon,
Tell me what billing systems are used by Russian cloud services, such as Megaplan, My warehouse, business365, Sky, Accounting Kontur, My business and the like? Or is it most likely "samopisnye" system?
I will be grateful for the answers, discussions.

Answer 1

Self-made)

Answer 2

there are many different ones, chargebee for example. It is convenient but works with a limited number of payment gateways. I think a lot of people use homemade ones.