Testing Credit-Card Numbers In E-Commerce Checkouts (Cheat Sheet)

As a developer, I work a lot with e-commerce websites and, as a result, with a lot of payment gateways. I’m fortunate that I get to work on many different projects for different clients, each with its own unique challenges. I have, therefore, found myself working with a lot of different payment gateways over the years, from the more familiar ones like PayPal and Stripe to some lesser known ones. While I love the variety of my work, I generally find working with payment gateways to be frustrating. I’m sure I’m not alone in this opinion! For many payment gateways, the documentation is poorly written, lengthy and, at times, difficult to find.