Killbill - Open-Source Subscription Billing and Payment Platform
Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.
Subscription Billing - Sales Order Processing that automates and manages cyclical and subscription based billings by generating invoices, quotes or orders in Dynamics GP.
Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.
Tossy - Create subscription based memberships & donations for India
Recurly - Subscription billing and recurring billing management. Recurly offers enterprise-class subscription billing for thousands of companies worldwide.