Over my years on the ComputerCraft Discord server, I've had the opportunity to witness the creation of numerous APIs/libraries of all sorts. I've gotten to examine these APIs in depth, as well as answer questions involving the APIs that the creators or users have. As an API designer myself, I compare the designs of other APIs with my designs, and I've noticed a number of patterns that make or break an API design. I've seen plenty of designs that make me go "WTF???", and lots that I just can't understand, even at my advanced level of programming (not to toot my own horn).
This article outlines some rules for making a sane API, which is easy to use, understandable, and doesn't make the user spin in circles to make things with it. Note that when I use the term "API", I'm primarily referring to code libraries and their public interfaces, but a number of points can be applied to web APIs as well. Since I have the most experience in Lua APIs, I'll be focu