SystemPay is a gem to ease credit card payment with Natixis Paiements / CyberplusPaiement bank system. It's a Ruby on Rails port of the connexion kits published by the bank.

EPC QR code for SEPA payments in any format

CloudPayments ruby client

Payments platform for marketplaces

GP webpay, easy to implement payment gateway

Integrates the mpay24 credit card and online payment processing system into the spree web shop

Integration of Stripe payment gateway for use with Piggybak

Adds Purchase Order as a Payment Method to Spree Commerce

Provides an interface to AzeriCard online payment processing system

An API for using the Amazon Flexible Payment Service (FPS).

Spree Engine for Conekta Mexican Payment gateway

This engine allows users to inject requests into a queue to be processed. The queue handles bank account validations, credit payments, debit orders and collecting bank statements/notify me statements.

Liqpay.com payment gateway integration for Spree E-Commerce.

This gem was designed to help you to access the locaweb payment gateway.

Sermepa is a spanish payments gateway

Payment Method for USA ePay SOAP Webservice

A gem to deal with Wechat payment.

Helping rubyist integration with cmb (China Merchants Bank) payment service (招商银行一网通支付) easier.

PingPlusPlus is the easiest way to accept payments online. See https://pingxx.com for details.

WebPay is payment gateway service in Japan. See also https://webpay.jp/.