Stripe
Stripe launched in 2010 as a developer-friendly payments API. The original pitch was simple: payments processing without the legacy banking infrastructure complexity. Over 15 years Stripe has expanded into a comprehensive financial infrastructure platform — payments, billing, tax, identity verification, banking, terminal hardware. The core remains payments processing; billing is an add-on capability.
Stripe Billing exists but is best understood as "subscription payments processing" rather than "subscription billing management." The feature set covers recurring charge processing, dunning, basic invoicing, customer portal. Operations with simple subscription models — flat monthly fee per user, simple usage-based pricing — find Stripe Billing sufficient. Operations with complex billing requirements (multi-product, complex prorations, usage-based with overages, revenue recognition) typically need a dedicated billing platform on top.