Metanga is an online billing and subscription payment service. Metanga offers merchants tools and features to bill for and accept payments for services and goods, either one-time payments or recurring subscription billing.
The Metanga API allows developers to access and integrate the functionality of Metanga with other applications. Some example API methods include managing account information, managing and editing product and price information, and managing billing. Public documentation is not available; interested developers should sign up here for more information: http://www.metanga.com/billing-system-demo-request/.