Building a Visual Regression Tool with VLMs and DOM Diffing

Hey Dev.to! I built a tool that combines DOM diffing with vision-language models (VLMs) for UI regression testing. Here's why and how.

The Problem with Current Visual Regression Tools

Ever used Percy, Chromatic, or Applitools? They catch real UI changes, but also flag tons of false positives from:

This creates "alert fatigue" — developers start ignoring reports because 80% are false positives.

The Key Insight