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.
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
Commerce.js - Rapidly create eCommerce experiences on web and mobile
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.
Shopify App Store - The most powerful ecommerce app store
Braintree - An all-in-one solution to accept, process, and split payments in your mobile app or online - from small business to large enterprise.