Browser DevTools are superb at going deep on one element. They're less good at the quick, page-wide questions developers ask dozens of times a day: *which images are missing alt text? what does this page look like without CSS? which headers did the server send? what's the heading outline?* Web Developer Tools answers those in one click each, from a single popup.
What's inside
555 tools are organised into categories in a sidebar, with search, so you never hunt through menus. The headline groups:
| Area | Highlights |
|---|---|
| CSS control | Disable all, linked or inline styles; switch to the border-box model; reload stylesheets; live-edit CSS in a side panel |
| Outline & structure | Outline block elements, headings, tables, positioned elements and external links to see a page's skeleton |
| Image auditing | Reveal alt text and dimensions, outline images missing alt, hide images, find broken images |
| Forms | Populate every field with sample data, clear forms, reveal passwords, enable disabled fields, flag inputs without labels |
| Element inspector | Hover any element for its box model, computed styles and ancestor breadcrumb |
| Color picker & ruler | Sample any pixel's colour; draw measuring rectangles and drop alignment guides |
| Reports | Searchable reports for CSS, images, forms, colours, document outline and response headers |
| Cookies & privacy | View, add and delete cookies; toggle JavaScript, popups, images or notifications per site |
Five things it makes faster
1. Seeing a page's real structure
Outline headings and you instantly see whether a page has one H1, skipped levels or headings used for styling. Outline block elements and positioned elements and layout bugs become obvious.
2. Accessibility spot-checks
Images missing alt text and form inputs without labels light up in place, which makes a five-minute accessibility pass realistic on every page you ship.
3. CSS debugging
Turn off all styles to check the content order, disable just inline styles to find the rule that's winning, or edit CSS live without opening DevTools.
4. Forms testing
Fill every field with sample data in one click, then clear it — far faster than typing test values by hand during QA.
5. Headers and cookies
Read the response headers report for caching and security headers, and inspect or edit cookies without leaving the page.
Pair it with web archives
A bug report often starts with “it used to work”. Open the page's history with Web Archive Viewer, find the last capture before the change, and run the same Web Developer Tools checks on the archived copy and the live page. Did the heading outline change? Did images lose their alt text in the redesign? Did a stylesheet stop loading? Comparing the two is often faster than reading the commit history — and our guide to comparing versions of a page shows how to diff the text and layout too.
Who it's for
- Front-end developers debugging layout, CSS and forms.
- QA testers running pre-release checks on many pages.
- SEO specialists checking headings, meta tags, links and headers.
- Designers verifying colours, spacing and alignment on the real page.
- Accessibility reviewers doing fast first-pass audits.
Want a concrete workflow? Read how to audit any website in 15 minutes, and browse the in-depth guides on the Web Developer Tools blog.
FAQ
Is Web Developer Tools free?
Yes — it's free to install and needs no sign-up. Get it on the Chrome Web Store, Firefox Add-ons or Edge Add-ons.
Does it replace Chrome DevTools?
No — it complements them. DevTools go deep on one element or request; Web Developer Tools makes page-wide checks one click each.
Does it send my pages anywhere?
No. The tools run locally in your browser.