Testing
DOM snapshots catch structural changes. Visual snapshot testing catches what DOM snapshots miss: layout shifts, color changes, font rendering differences, and the thousand small things that look fine in code but break in the browser. Percy and Chromatic are the two dominant tools in this space, and they take meaningfully
Testing
"Snapshot testing" gets used to mean two different things, and conflating them leads to wrong tool choices. DOM snapshot testing captures the HTML structure of a component. Visual regression testing captures what it actually looks like in a browser. These catch different bugs, cost different amounts to maintain,
Testing
Visual regression testing catches unintended UI changes by comparing screenshots of your components against known-good baselines. Storybook + Chromatic is the most widely adopted setup for this: Storybook provides isolated component renders across all states, and Chromatic handles screenshot capture, diffing, and the review workflow. This guide covers everything from initial
Testing
Argos CI is a visual testing platform that compares screenshots between your main branch and pull requests. When a PR changes the visual appearance of a component or page, Argos shows the before/after diff in GitHub and can block the PR until a team member approves the change. It
Visual Testing
Reg-Suit is a visual regression testing framework built around a plugin architecture. Unlike tools that are opinionated about screenshot capture, Reg-Suit focuses on the comparison and reporting layer — you bring your own screenshots, and Reg-Suit handles storage, comparison, and CI status reporting. Architecture Reg-Suit separates three concerns: 1. Screenshot capture
Visual Testing
Loki is a visual regression testing tool purpose-built for Storybook. It runs locally and in CI, captures screenshots of every story, compares them against stored references, and shows diffs when components change. Unlike cloud-hosted alternatives, Loki stores reference images in your repository and runs entirely offline. Why Loki Loki fills
Visual Testing
Happo solves a specific problem: visual regression testing across multiple browsers simultaneously. While Chromium-only tools catch 80% of visual regressions, cross-browser differences — font rendering, flexbox quirks, Safari's date inputs — require testing against real browser engines. Happo runs your components in Chrome, Firefox, Safari, and Edge and compares screenshots
Visual Testing
Visual regression testing catches UI changes that unit tests miss. Lost Pixel is an open-source visual regression testing platform that compares screenshots of components or pages across commits, flags differences, and integrates with your existing CI pipeline. Unlike hosted-only tools, Lost Pixel can run entirely in your own infrastructure. What
Visual Testing
BackstopJS is a visual regression testing tool that compares screenshots of web pages or components across versions. It's particularly useful for component libraries and design systems where you need to verify that changes to shared components don't break visual consistency across many consumers. How BackstopJS Works
iOS Testing
UI bugs are the ones users actually notice. A misaligned button, a truncated label, a broken dark mode layout — none of these are caught by a unit test that only verifies a view model property. Snapshot testing exists to close this gap. It captures the visual output of your UI
Testing
A developer changes a global CSS variable — --spacing-base: 8px becomes --spacing-base: 10px. All unit tests pass. All E2E tests pass. But twenty components now have slightly different spacing, the header overlap looks wrong on mobile, and a dialog's close button is partially hidden. No test caught it because
Testing
Percy is a visual testing platform from BrowserStack that integrates directly with Cypress and Playwright. You add a single command to your tests; Percy captures screenshots, compares them against approved baselines, and flags visual differences in a pull request review workflow. This tutorial covers setup for both Cypress and Playwright,