Landscapist is an API definition tool.
Because I hate writing Swagger, but it's a 'widely supported standard', and none of the other options are any better. So I decided to write my own ruby DSL for defining my APIs, with tools to generate Swagger.
bundle exec ./exe/landscapist swagger ~/workspace/myapp/doc/apis/apis.rb
bundle exec ./exe/landscapist typescript ~/workspace/myapp/doc/apis/apis.rb
bundle exec ./exe/landscapist server ~/workspace/myapp/doc/apis/apis.rb