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
FINAL CUT - Library for creating terminal applications with text-based widgets
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.
termbox - Termbox is a library that helps making terminal-based pseudo-GUIs.
Braintree - An all-in-one solution to accept, process, and split payments in your mobile app or online - from small business to large enterprise.
Slang - Slang is a powerful visual programming language using a newly developed stream-based paradigm.