Freedom251 › Website Accessibility Tools
Accessibility Visualizer
What Accessibility Visualizer is
Accessibility Visualizer is a free, MIT-licensed browser extension that overlays accessibility information on web pages. It can display image alternative text, heading levels, form labels, table structure, lists, language attributes, and WAI-ARIA information. Warning and error messages identify problematic states, including states that need caution. Live-region changes can be shown visually for status, alert, log, aria-live, and output elements. Users can switch presets, choose displayed information, and save settings for each domain. The maker links to Chrome Web Store and Firefox Add-ons; the Firefox listing also covers Firefox for Android. The extension processes information locally and says it does not collect, store, or transmit personal or browsing data. Browser storage may keep preferences, while browser sync can synchronize them through the browser account. Source code is publicly available under the MIT License. The guide calls the information supplementary and recommends checking with actual assistive technologies such as screen readers.
Who it suits
It suits developers and people checking web-page accessibility who want visible overlays without first inspecting the accessibility tree or source code. It can complement axe DevTools, WAVE, and Lighthouse.
What it does well
- Free MIT-licensed extension
- Displays headings, labels, tables, and ARIA
- Visualizes live-region changes
- Domain-specific settings can be saved
- Processes page information locally
What to know first
- Overlay information is supplementary
- Some sites may slow down
- Frames or Shadow DOM can block overlays
- Interactive mode may affect mouse operations
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Free | MIT-licensed browser extension | Free |
As ymrl.github.io lists them, read 12 Oct 2026. The maker's own page has the final word.
Verdict
Accessibility Visualizer provides a configurable visual layer for noticing accessibility details while coding or reviewing pages. It is a supplement, not a replacement for testing with assistive technologies.
Facts from Accessibility Visualizer's own pages
- Available browsers
- The maker links to Chrome Web Store and Firefox Add-ons; the Firefox listing says the add-on is also available in Firefox for Android. · ymrl.github.io, 12 Oct 2026
- Browser extension
- Yes · ymrl.github.io, 22 Sept 2026
- Customization
- Users can switch among presets, select which information to display, and save different settings for each domain. · ymrl.github.io, 12 Oct 2026
- Free plan
- Yes · ymrl.github.io, 22 Sept 2026
- Integrations
- The guide lists axe DevTools, WAVE, and Lighthouse as tools it can be used alongside. · ymrl.github.io, 12 Oct 2026
- Intended users
- The maker describes the goal as helping people notice accessibility while coding or checking web page behavior, without first needing to inspect the accessibility tree or source code. · ymrl.github.io, 12 Oct 2026
- Issue detection
- The extension displays warning and error messages for problematic states and states that should be used with caution. · ymrl.github.io, 12 Oct 2026
- Live regions
- It can visually show changes in live regions, including those using role=status, role=alert, role=log, aria-live, and output elements. · ymrl.github.io, 12 Oct 2026
- Open source
- The project is released under the MIT License, and its source code is publicly available. · github.com, 12 Oct 2026
- Performance and display limits
- The guide notes that some sites may slow down, frames or Shadow DOM may prevent overlays from appearing, and interactive mode may interfere with mouse operations. · ymrl.github.io, 12 Oct 2026
- Privacy
- The privacy policy says the extension does not collect, store, or transmit personal or browsing data and processes information locally in the browser. · github.com, 12 Oct 2026
- Product
- Accessibility Visualizer is a browser extension that overlays accessibility information on web pages. · ymrl.github.io, 12 Oct 2026
- Scan scope
- page · ymrl.github.io, 22 Sept 2026
- Settings storage
- The extension may store preferences using browser storage; browser sync may synchronize them under the user's account, with the browser vendor handling that process. · github.com, 12 Oct 2026
- Verification limit
- The guide says the extension's information is supplementary and recommends checking with actual assistive technologies such as screen readers. · ymrl.github.io, 12 Oct 2026
- Visualized information
- It can display image alternative text, heading levels, form labels, table structure, lists, language attributes, and WAI-ARIA information. · ymrl.github.io, 12 Oct 2026
Where Accessibility Visualizer stands on Freedom251
- Website Accessibility Tools#81 of 133