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.

Automate API workflows. Chain HTTP requests. Validate. Zero code.

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

Sonic is a platform that integrates remote control debugging and automated testing of mobile devices, and strives to create a better user experience for global developers and test engineers.

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.

Mockoon is the easiest and quickest way to design and run mock REST APIs.