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Generate massive amounts of fake data for testing

HTTP assertions for Node.js

Open-source load testing for web applications

The most popular Python testing framework

Simple, complete React component testing utilities

Generate massive amounts of fake data in the browser and Node.js

Flexible API mocking and stubbing for tests and development

API mocking via Service Workers for browser and Node.js

Consumer-driven contract testing for microservices

Incredibly fast all-in-one JavaScript runtime, bundler, and package manager.

Email sandbox for testing and transactional API for production sending

Integration testing with real Docker-based dependencies — no mocks needed

Cloud testing on 3,000+ real browsers and mobile devices

LLM observability, tracing, and testing platform from LangChain

Local Kubernetes cluster for development and testing

CI/CD automation built into GitHub with event-driven workflows

Open-source load testing tool for engineers

Zephyr plugin agent

An ESLint plugin for projects using Cypress

Preview your Jest tests in a browser

A superset of the JSDOM environment for Jest that respects Node.js globals.

mocking window.matchmedia with vitest

Custom Vitest matcher for testing accessibility with aXe. Forked from jest-axe.

Fake SMTP Server for email testing