Subscription Payments by involve.me - Launch a subscription business in one day
SolidInvoice - SolidInvoice is simple to use online invoicing software that helps small businesses to get paid faster on time.
Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.
JustOn - JustOn offers electronic billing and invoicing solutions.
Quiken - All-in-one client and request management platform.
Upodi - Unified Commerce Platform.