RestPilot от Idrees Kema

RestPilot is a lightweight and intuitive REST API testing tool designed for developers who want speed and simplicity. Easily send GET, POST, PUT, DELETE, and other HTTP requests with custom headers, authentication, and body data. View formatted responses in JSON or raw mode, save requests for reuse, and quickly debug your APIs — all within your Firefox browser.
Perfect for developers, testers, and API enthusiasts looking for a fast, no-nonsense alternative to heavy API clients.