Voiden is a developer-first API client with local storage, Git-integrated, all based on markdown + offline support.

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.

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.

A modern, resource-friendly REST client for Windows 10

Monitor network requests and API failures with real-time insights

Hand-crafted lightweight Rest Client for testing APIs. Supports collections, environments, git collaboration and local storage.