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

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

Hoppscotch is an open-source API development ecosystem that helps you create and test your API requests saving precious time in development.

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

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.

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.