We started FoxyCart.com in 2007 and soon after slapped together some XML and called it an API. As our customer base grew and third-party integrations emerged, the need for a true REST API became a priority. Beginning in 2012, we started researching best practices for modern API development. This talk will tell the story of that research and 10-months of development that followed. You'll get a look at the HAL hypermedia format along with some best practices we came up with for our problem domain of exposing our entire admin interface. We'll cover a lot. You may need a seat belt.