Braintree - An all-in-one solution to accept, process, and split payments in your mobile app or online - from small business to large enterprise.
Shopify - Shopify is a powerful ecommerce platform that includes everything you need to create an online store and sell online. Try it free for 14 days.
Razorpay - Payment gateway solution for India with robust, developer friendly API and simple economic pricing.
Commerce.js - Rapidly create eCommerce experiences on web and mobile
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
Shopify App Store - The most powerful ecommerce app store