Jest is a delightful JavaScript Testing Framework with a focus on simplicity.

Real API Design-first Development Platform Design. Debug. Test. Document. Mock. Build APIs Faster & Together.

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

Design, debug, and test APIs locally or in the cloud

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.

Requestly is an open-source tool that simplifies API development, testing, mocking, and integration for developers and QAs.