Free & OpenSource REST API Testing Tool for all levels in a Test Pyramid

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

REST API client library for .NET

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

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.

HyperTest is a no-code test automation tool that regresses all your APIs by auto-generating integration tests using your network traffic, also giving a way to reproduce these failures inside actual user-journeys.