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

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

Professional software tool for HTTP testing and debugging

Burp or Burp Suite is a set of tools used for penetration testing of web applications. It is developed by a company named Portswigger who make freely available a Web Security Academy which has a range of lessons on penetration testing.

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

Streamline your API testing, integration testing and test data management.