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

Simulate APIs, integrations, and environments at enterprise scale.

RapidAPI for Mac is a full-featured HTTP client that lets you test and describe the APIs you build or consume. It has a beautiful native macOS interface to compose requests, inspect server responses, generate client code and export API definitions.

Built for developers and testers alike, SoapUI is the only open source tool that covers the entire testing spectrum (functional, security, load, mocking).

Test, scrape, generate, and automate without the pain and expense of hosting your own headless browsers.

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