Open API Specification is a machine and human readable way to describe APIs. From these specs we can generate documentation, create libraries, and ensure that our users know exactly what to expect from our APIs. This talk shows you around OAS from the very beginning, from introducing JSON and YAML for the data format and working up from there. You’ll learn how to represent your APIs and how to structure and navigate the spec documents. There will also be recommendations for resources and tools to help you along your way. This talk will showcase some of the things that your API can do when it has an OAS to describe it. This session is recommended for writers looking to become more API-savvy and API engineers wanting to make their APIs more useful to their users.