Content
Visual Regression
A visual regression is an unintended visual change to a webpage — a button moved, text colour changed, a section disappeared, an image broken — caused by a code or content update. Visual regression testing automates the detection of these changes.
Part of Visual monitoring — the full answer, the facts and the alternatives in one place.
In depth
A visual monitor captures a screenshot of each tracked page on a schedule (or after every deploy), then pixel-diffs the new image against the previous baseline. Significant differences are flagged for human review with the changed regions highlighted.
Good visual monitoring includes ignore-zones (for ads, timestamps, A/B test variants that legitimately change), responsive variants (desktop + mobile + tablet), and authenticated states (post-login screens).
Why it matters
Many of the worst production bugs are visual — a CSS change that hides the buy button, a CMS edit that removes the pricing section, an A/B test that breaks the navigation. Functional tests miss these. Visual regression catches them within minutes.
How Lemwatch helps with visual regression
Lemwatch monitors visual regression continuously and alerts you the moment something changes.
Visual monitoring →Related terms
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Change detection is the practice of monitoring a webpage for content modifications and alerting when something…
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Broken Link
A broken link is a hyperlink that no longer points to a working destination — typically returning a 404 (not f…
Browse the full Lemwatch monitoring glossary (47 terms).