Mocker is a self-initializing fake implemented as a reverse proxy that supports different record/playback modes.
It records HTTP interactions in a file-system so they can be later replayed during local development or in broad stack tests, precluding the need for access to real external services.
Mocker is implemented in JavaScript, it has zero dependencies, and can be used either as a command-line tool or as a library.
brew tap caiogondim/tap
brew install mocker
mocker --help
More info on docs.