# Component Testing

Visual testing for Storybook

Chromatic is a Storybook-first visual testing and UI review platform for design systems and frontend teams. It publishes Storybook, captures component snapshots, reviews pull-request diffs, and supports interaction tests, accessibility checks, TurboSnap, SteadySnap, Playwright/Cypress workflows, and Storybook MCP context.

Console for mobile browsers

Open-source mobile web console that embeds a full developer toolkit into any mobile browser. Provides console, element inspection, network monitor, resource viewer, performance timing, and JavaScript execution on devices that lack native DevTools. The de facto standard for debugging responsive layouts, mobile-specific JavaScript errors, and production issues on phones — loaded with a single script tag or a browser extension.

Open-source visual regression testing tool

Lost Pixel is an open-source visual regression testing tool that serves as an alternative to Percy and Chromatic. It captures and compares screenshots of UI components and application pages across Storybook, Ladle, Histoire, and custom screenshot sources like Cypress or Playwright. Integrated directly into GitHub Actions pipelines, it detects unintended visual changes before they reach production, with a free SaaS tier available for open-source projects.

Open-source MCP bridge between AI assistants and the Unity Editor

MCP for Unity is CoplayDev’s MIT-licensed bridge between MCP-compatible AI assistants and the Unity Editor. It exposes tools for assets, scenes, GameObjects, scripts, tests, profiling, and build-oriented workflows. The community project supports Unity 2021.3 LTS through 6.x and is explicitly not affiliated with Unity Technologies.

UI component workshop

Storybook is an open-source workshop for building, documenting, and testing UI components in isolation. Render every visual state of React, Vue, Angular, Svelte, or Web Components, write interaction tests, visual regression tests, and accessibility checks, and publish a living design reference. Trusted by thousands of teams including GitHub, Airbnb, Shopify, and Microsoft as their single source of UI truth.

Sentry-maintained MCP server and CLI for Xcode builds, simulators, and tests

XcodeBuildMCP is a Sentry-maintained, MIT-licensed MCP server and CLI for agent-assisted iOS and macOS development. It lets MCP-compatible coding agents run Xcode build and test workflows, manage simulators, inspect failures, and work through Homebrew, npm, or on-demand client configuration, with documented Sentry telemetry controls for teams that need an opt-out.