Felt for iPhone - Handwritten cards for the modern world

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.

43 Layers - Marketplace for custom gifts and decorations

SuperPay - Get paid faster with your own custom payments page

GiftStarter - Crowdfunded gift-giving and gift concierge

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