Best 7 Tools for Validating API Responses in 2025
Verify that API responses meet expected formats, data types, and business logic through automated assertions. Essential for QA engineers and developers who need to ensure APIs return correct data and handle various scenarios properly.
Paw
Paw
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.
Thunder Client
Thunder Client
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.
Insomnia
Insomnia
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.
Testfully
Testfully
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
Hoppscotch
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.
Bruno
Bruno
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."
Postman
Postman
Postman is an all-in-one platform for working with APIs throughout their entire lifecycle. It provides tools to send API requests, view responses, write tests, create documentation, and monitor performance. Unlike basic HTTP clients, Postman offers a complete environment where teams can organize their work into collections, share them with teammates, and automate testing.