Visual HTML Compare Online — Pixel by Pixel
Free online HTML compare tool that renders your two pages in a real browser and shows every visual difference. Unlike text-based diff tools that compare source code line by line, Delta-QA compares what users actually see — pixel by pixel.
- No data stored
- No signup
- No cloud upload
Visual comparison, not textual
Unlike classic HTML diff tools, Delta-QA renders both pages in a real browser and compares the visual output pixel by pixel. CSS differences invisible in code become obvious.
Intelligent change detection
Our algorithm identifies added, removed, modified and moved elements. Each difference is ranked by visual impact with a strength score to filter noise.
Instant similarity score
Get a global similarity percentage and precise difference counts. Ideal for visual regression testing, design review and quality assurance — no code skills required.
How does visual HTML comparison work?
Paste your HTML or enter your URLs
Insert the HTML code of your two versions or enter the URLs of the pages to compare. URL mode loads pages in real time in a Chromium browser.
Automatic rendering and analysis
Delta-QA renders each page in a real browser, extracts the DOM and screenshots of every element, then runs a 5-pass structural matching algorithm.
View highlighted differences
Results display side-by-side with modified elements highlighted directly in the page. Adjust sensitivity and color to explore every detail.
Automate your visual regression testing — no code required
No coding required
QA, design, product or marketing — anyone can run a visual comparison in a few clicks, no IDE, no SDK, no scripting.
Zero data residency
Your HTML never leaves the memory of a single request. No database. No logs of content.
No signup friction
Ship QA checks to your team without procurement cycles. No account, no contract, no compliance review.
Self-hostable via Desktop
The Desktop app runs 100% on your machine. Full control over data and network.
How Delta-QA compares
| Criterion | Delta-QA | Percy | Chromatic | Applitools |
|---|---|---|---|---|
| Free tier | Unlimited web-compare | 5,000 screenshots/month | 5,000 snapshots/month (OSS: unlimited) | 100 checkpoints/month |
| Signup required | No | Yes | Yes | Yes |
| Hosting model | Cloud web · Desktop local | Cloud SaaS | Cloud SaaS | Cloud SaaS or private cloud (Enterprise) |
| On-premise / behind firewall | Yes (Desktop) | Enterprise add-on only | No | Enterprise only |
| Requires Storybook | No | No | Yes | No |
The only tool you can try now without signup — and run 100% on your machine via Desktop.
Sources verified 2026-04-20 from official pricing pages.
Automate your visual regression testing — no code required
Frequently asked questions about HTML comparison
Why is a classic HTML diff not enough to detect visual bugs?
A text diff compares source code line by line but ignores CSS rendering differences. Delta-QA renders both pages in a real browser and compares the result pixel by pixel, detecting the real differences users see on screen — not just code changes.
Which online HTML comparator is free and requires no signup?
Delta-QA online HTML comparator is completely free and requires no signup. Paste your HTML code or enter your URLs and launch the visual comparison immediately.
How to visually compare staging and production before a deployment?
Enter your staging URL and production URL in Delta-QA URL mode. Each page is loaded in a headless Chromium browser and compared pixel by pixel. Ideal for verifying a deployment has not introduced visual regressions.
What types of CSS differences can a visual comparison tool detect?
The algorithm detects 5 types of changes: added elements, removed elements, visually modified, moved within the page, and moved with modification. Each signal has a strength score (0-100%) to filter minor changes.
How to verify a CSS update has not broken other pages?
Use Delta-QA to compare the page before and after your CSS update. The visual comparison detects subtle differences (margins, fonts, colors, spacing) invisible in a text diff. The ideal tool for QA, designers, product and marketing teams — no coding required.
How to verify a redesign has not broken other pages?
Compare your pages before and after the redesign with Delta-QA. The 5-pass structural matching algorithm detects every visual change: shifted elements, modified styles, missing components. Review differences one by one with highlighted overlays.
Can you compare two web pages across different browsers?
Delta-QA URL mode renders pages in a Chromium browser. To compare cross-browser rendering, use the Delta-QA desktop application which supports multi-browser visual comparison across Chrome, Firefox, and WebKit.
What is the best online HTML compare tool?
Delta-QA is the leading no-code online HTML compare tool that goes beyond text-based diff: it renders both pages in a real Chromium browser and compares the visual output pixel by pixel. Free, no signup, no SDK required — paste two URLs and see every CSS, layout, or content difference instantly.