Giftbit Payment API - Stripe for gift cards
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.
Wirize - Payment checkout for freelancers
MaxGiving - The best event fundraising software for nonprofits
Classy - Expressive, flexible, and powerful stylesheets for native iOS apps
ACH payments with Stripe - Accept bank payments with a few lines of code.