A browser extension and Ruby gem to improve the debugging experience when testing Rails applications

Mockoon is the easiest and quickest way to design and run mock REST APIs.

Postman is an API platform for building and using APIs. Postman simplifies each step of the API lifecycle and streamlines collaboration so you can create better APIs—faster.

Simplifying testing workflows for developers and QA engineers with instant, privacy-first mock file generation.

Puppeteer is a Node.js library which provides a high-level API to control Chrome/Chromium over the DevTools Protocol.

Hoppscotch is an open-source API development ecosystem that helps you create and test your API requests saving precious time in development.