Visual regression testing

Visual regression testing (VRT) catches unintended UI changes by taking screenshots of every component and comparing them to a baseline on each commit. If a refactor accidentally shifts a button by 2px, VRT flags it before it ships. For a design system shared across many products, this is essential — a small token change can ripple in unexpected ways.

Chromatic, Percy, Lost Pixel and Playwright's built-in screenshot comparison are the common tools. The pattern that works: run VRT against Storybook stories so coverage maps to your existing component catalogue, review diffs in PR, and treat unintentional changes as bugs rather than "looks fine to me" rubber-stamps.

Related: Storybook · Component · Component-driven development · Design QA