Postman - The Collaboration Platform for API Development
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
Django REST framework - Django REST framework is a toolkit for building web APIs.
Amazon Pay - Amazon Pay is an online payment service that makes checkout on your site fast and secure for hundreds of millions of Amazon customers around the world.
Amazon API Gateway - Create, publish, maintain, monitor, and secure APIs at any scale
Braintree - An all-in-one solution to accept, process, and split payments in your mobile app or online - from small business to large enterprise.