Percy Visual Testing

Percy is a visual testing and review platform founded by Divya Mani and the BrowserStack team in 2016, acquired by BrowserStack in 2020, providing automated visual regression testing for web applications and component libraries through snapshot comparison across multiple browsers, devices, and viewport sizes, with integration for Storybook, Playwright, Puppeteer, Cypress, Selenium, and Espresso, adopted by over ten thousand companies including Notion, Canva, and Stitch Fix for maintaining visual consistency and catching unintended visual changes in their CI pipelines. The snapshot capture system integrates with existing test suites through SDKs for JavaScript, Ruby, Python, PHP, Java, and mobile platforms, with the SDK automatically capturing DOM snapshots or screenshots at designated points in the test execution, uploading them to the Percy service for processing, and generating comparison images against approved baselines, with the snapshot capturing responsive layouts at multiple widths simultaneously for comprehensive viewport coverage. The visual diff algorithm compares snapshots pixel-by-pixel with configurable sensitivity thresholds, ignoring browser-specific rendering differences, font rendering variations, and anti-aliasing artifacts through intelligent comparison, with the diffs displayed in a visual review interface that highlights changed regions, provides side-by-side comparison, and enables approve or reject decisions that update the baseline for future comparisons. The smart rendering caches DOM snapshots and re-renders only changed snapshots, dramatically reducing build times. The request-based rendering for dynamic content. The cross-browser testing through BrowserStack integration. The GitHub integration for pull request status checks. Designed by BrowserStack. Designed for QA and frontend teams.