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.

Professional software tool for HTTP testing and debugging

Test, scrape, generate, and automate without the pain and expense of hosting your own headless browsers.

Jest is a delightful JavaScript Testing Framework with a focus on simplicity.

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

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