The first thing to know is that an OpenAPI specification must be a valid JSON document. The specification also explicitly allows YAML, which is a superset of JSON and can be converted to JSON. We will be using YAML because it is more readable (and thus writable) by humans, even for non-developers. Furthermore, you can add comments inside YAML files, something that's not possible with JSON.
Let's start by learning the basics of YAML. We only need to learn a few basic pieces of syntax to write our OpenAPI specification.
Like JSON, getting started with the basic syntax for YAML is very simple. All YAML documents start with three dashes (---) to indicate the start of the file, and three periods (...) to indicate the end of the file. ...
