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.

Bruno is a Fast and Git-Friendly Opensource API client, aimed at revolutionizing the status quo represented by Postman, Insomnia and similar tools out there.

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

REST API client library for .NET

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

Design, debug, and test APIs locally or in the cloud