Best 20+ AI API Tools to use in 2025

Builder.io is a platform that bridges the gap between design and code. It has two main products that work together: Fusion Visual IDE for building applications and Publish Visual CMS for managing content.

Replit is an online platform where you can write code, build apps, and publish them to the internet, all from your browser. No downloads or installations needed. It works like Google Docs but for creating software.

Thunder Client is a REST API testing tool that lives inside Visual Studio Code. You can send requests, check responses, and organize your API tests without opening another program. It works just like other API testing tools but runs directly in your code editor.

Katalon is a complete testing solution that automates the process of checking if software works correctly. Instead of testing applications manually every time, Katalon lets you create automated tests that run on their own.

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.

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.

Paw is a complete API testing and development tool designed for Mac computers. You can use it to create and send HTTP requests, then see detailed responses with headers, status codes, and body content. The app supports all common HTTP methods including GET, POST, PUT, DELETE, and PATCH.

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.

Testfully is a platform that helps developers test and monitor APIs during development and after deployment. You can use it to send requests to your APIs, create automated tests, and set up monitoring to catch problems before they affect users.

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.