A symbolic execution based autonomous unit test generation tool. Comes with a free CLI version for real-time testing, and server version for larger scopes, build service and CI/CD integration.

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

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

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

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.

RapidAPI for Mac is a full-featured HTTP client that lets you test and describe the APIs you build or consume. It has a beautiful native macOS interface to compose requests, inspect server responses, generate client code and export API definitions.