Active Merchant

Active Merchant is a Ruby library designed to provide a simple and unified API for handling payment transactions in e-commerce applications. Originally created to meet Shopify’s need for integrating with numerous payment gateways, it is widely used in modern Ruby applications for secure financial transactions. Maintained by Shopify and Spreedly, it can be seamlessly integrated with Ruby on Rails or used as a standalone library, making it ideal for developers working with online payment systems.