Top TESTING GitHub Repositories & Tools (2026)

Hunt down social media accounts by username across social networks

Playwright is a framework for Web Testing and Automation. It allows testing Chromium, Firefox and WebKit with a single API.

HarnessRouter Community Edition: the self-hosted, Apache-2.0 edition of the unified interface for agent harnesses. Run Codex, Claude Code, Hermes, PI, DSH, and more through one API, with sessions, streaming, files, cancellation, and failure handling. Implements the Unified Harness Protocol (UHP), an open standard. Your keys, your infrastructure.

A list of useful payloads and bypass for Web Application Security and Pentest/CTF

Fast web fuzzer written in Go

Open-Source API Development Ecosystem • https://hoppscotch.io • Offline, On-Prem & Cloud • Web, Desktop & CLI • Open-Source Alternative to Postman, Insomnia

Coverage, security and code quality for coding agents

A sandbox for the third-party APIs you depend on. Built from the provider's spec, it fails on purpose, and it replays the exact failure production hit.

Detect breaking changes between OpenAPI 3.0/3.1 specs. Explainable Web UI, CLI and CI gate; local-first and deterministic, with optional AI summaries.

802.11 Attack Tool

Plugin for JADX to integrate MCP server

Flagsmith is an open-source feature flag platform with remote config, experimentation, and self-hosted or cloud deployment options.

Storybook is the industry standard workshop for building, documenting, and testing UI components in isolation

Property-based testing for web and terminal UIs

A Burp Suite extension that exposes the full Montoya API as a local REST API, with Swagger UI

Open-source AI penetration testing tool to find and fix your app’s vulnerabilities.

Mobile app automation and verification for AI coding agents. CLI, MCP server, and typed Node.js API for iOS, Android, HarmonyOS, TV, web, macOS, and Linux.

☕️ Classic, reliable, trusted test framework for Node.js and the browser

JavaScript Testing utilities for React

🐐 Simple and complete React DOM testing utilities that encourage good testing practices.