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

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

Don’t just observe. Take action. The only app monitoring platform built for developers that gets to the root cause for every issue.

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

Mock and modify HTTP request for exploratory testing.

Sonic is a platform that integrates remote control debugging and automated testing of mobile devices, and strives to create a better user experience for global developers and test engineers.