ActiveMerchant is a payment/shipping library for Ruby. This is more of an independent billing engine that also gives an API for payment gateways but also handl

ActiveMerchant is a payment/shipping library for Ruby. This is more of an independent billing engine that also gives an API for payment gateways but also handles customer records, automatic customizable emails for billing events (purchases, subscriptions, renewals, cancellations, etc.), handles auto-recurring billing across all gateways, and allows you to distribute API keys with separate API and control panel clients.