Best Tools For API Testing

Validate your API's functionality with these top tools and resources. Our collection features free and paid options for testing APIs, gRPC requests, GraphQL queries and service mocking.

FirecampFree with Paid Option

Firecamp is multi protocol API platform for Developers.

Thunder Client is a lightweight Rest API Client Extension for Visual Studio Code

Snapshot-based stub/mocking of APIs.


GUI client for gRPC/gRPC-Web

ProAutoma API TesterFree with Paid Plan

Online REST API client

MockoonFree with Paid Plan

Create mock APIs in seconds

Mock API by intercepting requests on the network level. Seamlessly reuse the same mock definition for testing, development, and debugging.

Node.js mock server running live, interactive mocks in place of real APIs


Mock API calls seamlessly


Run mock server based off an API contract with one command

A flexible, lightweight JSON Data validator and formatter

mock object testing framework that can be used to create stubs in iOS apps.

A better API testing tool


Automatically mock your HTTP interactions to simplify and speed up testing


ReqBin is an online API testing tool for REST and SOAP APIs.

HTTP Request & Response Service, written in Python + Flask.


The most popular and friendly mocking framework for .NET

Code Generator for HTTP Requests

Learn everything there is to know about REST apis with the this opensource resource.

Security and reliability for JavaScript applications

A text-based HTTP client in the browser, an interface-less Postman.

An easy way to execute a health check against your API endpoint.

HTTP assertions made easy via superagent

Over the wire test doubles

It’s a free and open source interactive HTTPS proxy


command line tool and library for transferring data with URLs

PostmanFree version

API Testing Tool