Render your Android screens without a physical device or emulator.

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

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

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

Loader.io is a free load testing service that allows you to stress test your web-apps & apis with thousands of concurrent connections.

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.