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.
PayPal - PayPal is the faster, safer way to pay online without sharing financial details, send and receive money or accept credit and debit cards as a seller
UniPayGateway - Ultimate payment gateway software for merchants, ISOs and PSPs. Full range of payment gateway capabilities. Functionality rich open source payment system.
Zuora - Zuora creates cloud-based software on a subscription basis that enables any company in any industry to successfully launch, manage, and transform into a subscription business.
Payoneer - Whether making international payments, receiving funds, managing your digital business, or accessing capital, Payoneer opens your business up to the world.
Skrill - Skrill (formerly known as Moneybookers) is the cheaper way to send and receive money worldwide.