Best 4 Tools for Mocking APIs in 2026
Create simulated API servers that mimic real API behavior for development and testing purposes. Essential for developers who need to build and test applications before backend APIs are fully developed or available.
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.
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.
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.
Firecamp
Firecamp
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.