API Analysis Tooling

As I study each API, and API related service, I'm always looking for open source tooling that has been developed around each area of the API life cycle. This is an aggregate of tooling I've come across and aggregated as part of my API analysis research.

If there is a tool that you think should be listed here, let me know by submitting a Github issue or Tweeting a link at me. I'm always looking for new types of tools, and get better at organizing them here and making sense.