Best 6 Open Source Testfully Alternatives in 2025

Insomnia is a desktop application that lets you test and work with APIs. Think of it as a specialized tool for developers who need to send requests to APIs and check the responses they get back. It supports all major API types, so you don't need different tools for different projects.

Bruno is an "offline-first API client" that revolutionizes how developers test and manage APIs. Instead of forcing you to create accounts or store data in the cloud, Bruno saves everything directly on your device using a simple text format called "Bru."

Hoppscotch is an API development environment that runs in your web browser. You can test any API by sending requests and viewing the responses instantly. Unlike traditional tools, Hoppscotch is completely free and open-source, meaning anyone can use it or even contribute to improving it.

HTTPie is a tool designed for testing APIs and HTTP servers with an easy-to-understand approach. You type commands that look similar to the actual HTTP requests you want to make, and HTTPie handles the technical details for you. The responses come back formatted with colors, making JSON and other data easy to read.

Firecamp is a multi-protocol API development tool that helps you test and build APIs with ease. Unlike traditional API clients that focus mainly on REST, Firecamp offers dedicated GUI playgrounds for REST, GraphQL, WebSocket, and Socket.IO protocols all in one application.

SoapUI is a testing platform that checks how APIs and web services perform. You can use it to send requests to your API, check the responses, and make sure everything works as expected. It runs on Windows, Mac, and Linux computers because it is built using Java.