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.

Real API Design-first Development Platform Design. Debug. Test. Document. Mock. Build APIs Faster & Together.

API Testing Platform that automatically generates unit test cases with dependency mocks from API calls

Fully integrated API and web service testing capabilities that automate end-to-end functional API testing.

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

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