When you first start building an API for a new product you mostly focus on getting an MVP ready, with the goal shipping as soon as possible so you can get feedback from customers. If you are lucky enough, your product will be successful and you will have to start worrying about things like authentication, authorization, documentation, validation, rate limiting, geo-redundancy, and no downtime deployments. In this talk I will go over some real life examples of our experience evolving our APIs at Auth0 and some of the tools we use for that.