title: Open payment gateway libraries for Java, Python, Ruby, Node.JS, and PHP
body: <p>I'm looking for generic and open source payment libraries that support many different payment processor APIs. In other words, I'd like to develop an application using a single payment processing API, but be able to easily switch between payment gateways, such as Authorize.Net, Payflow Pro, Braintree, PayPal, Google, Amazon, etc.</p>
  
  <p>This question gives some <a href="https://stackoverflow.com/questions/2242653/java-payment-gateway-library">Java solutions</a>, but the suggestions all look horrible. Isn't there anything more like ActiveMerchant for Java? I really need a good Java solution, to the point of building my own if necessary. But I don't want to reinvent the wheel if it exists.</p>
  
  <p>Are there any solutions for Python, Node.JS, or PHP?</p>
  
  <p>Ideally, I'd like to find something similar to Ruby's <a href="http://www.activemerchant.org/" rel="nofollow noreferrer">ActiveMerchant</a>, which looks exceptionally complete. Are there any other Ruby solutions?</p>