If you ask most developers “What’s your favorite API?” you’ll get a variety of answers that fall into a few categories. Most people think of APIs that let them accomplish something important or an API that made them feel powerful or an API that made it all click for them. When I think of my favorite API, I think of Amazon’s Sales Tax API. To explain why, I need to step into the ancient Internet history of 2002. Enter the Bezos Memo Around that time, Jeff Bezos wrote what has since become known as the “Bezos Memo.” In it, he laid out the Vision for Amazon’s internal systems and infrastructure and laid the groundwork for what would become AWS. Here are the paraphrased key points: All teams will henceforth expose their data and functionality through service interfaces Teams must communicate with each other through these interfaces There.