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

Simulate APIs, integrations, and environments at enterprise scale.

Voiden is a developer-first API client with local storage, Git-integrated, all based on markdown + offline support.

Build and test APIs easily

Swagger UI allows anyone — be it your development team or your end consumers — to visualize and interact with the API’s resources without having any of the implementation logic in place

Selenium automates browsers. That's it! What you do with that power is entirely up to you.