When looking at the world of API formats, you know by now that there are two big players: XML and JSON. As human-readable formats, these two have owned the format world for more than a decade.

As is often the case, developers and technologists rarely settle happily for something for long. XML was number one for a very long time before the computational complexity of encoding and decoding as well as the verbosity of schema pushed many developers towards JSON.

JSON is not without its faults either. It's not all that readable by humans without some explicit spacing, which then increases the size of the document excessively. It doesn't handle commenting by default either.

There are a number of alternative formats that are sitting on the sideline. YAML, which stands for YAML Ain't Markup Language, is a whitespace-delimited format that uses indentation to make it extremely readable for humans. An example document would look something like this:

---
api:
  name: Social...