Free Screen Change Detector: Compare Screenshots and Find Differences in 2026

What is a Screen Change Detector?

A screen change detector is a tool that compares two screenshots and highlights the differences between them. This is incredibly useful for QA testing, visual regression testing, monitoring UI changes, and ensuring consistency across different versions of your application.

Our free screen change detector tool allows you to upload two screenshots and instantly see what changed. The tool highlights differences in red, making it easy to spot even subtle changes in your UI.

How to Use Our Free Screen Change Detector

1. Upload Your Before Screenshot - Start by uploading the original screenshot
2. Upload Your After Screenshot - Upload the screenshot you want to compare
3. Click Compare - The tool will automatically detect and highlight all differences
4. Review Changes - Red areas indicate what changed, gray areas are unchanged

The tool works entirely in your browser - no data is sent to servers, ensuring your screenshots remain private.

Use Cases for Screen Change Detection

QA Testing
Compare screenshots before and after code changes to quickly identify visual regressions or unintended UI modifications.

Visual Regression Testing
Automate your visual testing workflow by comparing screenshots across different browser versions, devices, or screen sizes.

UI Monitoring
Monitor your application's UI for unexpected changes, especially useful for monitoring production deployments.

Design Review
Compare design mockups with implemented versions to ensure pixel-perfect accuracy.

Automate Screen Change Detection

While our free tool is great for manual comparisons, you can automate screen change detection with MonitorSensei. Set up monitors to automatically detect when specific visual states change on your screen, and get instant notifications when changes occur.