axe-core Engine
Runs the industry-standard axe-core 4.9 engine against all WCAG 2.1/2.2 AA rules and best-practice checks — the same engine used by major enterprise teams.
Open Source · Powered by axe-core 4.9
Web Accessibility
Testing for Developers
Scan WCAG 2.1/2.2 AA violations in real-time. Get a 0–100 score, colored DOM overlays, and a full DevTools panel — all inside Chrome.
Features
Everything you need to fix accessibility
From a quick popup score to a deep-dive DevTools panel — a11y DevTools covers the full testing workflow.
Score 0–100
A single actionable score with letter grade A–F, calculated from violation counts weighted by impact level. Track page improvements over time.
DOM Highlighting
Colored overlays paint directly onto the live page — red for critical, orange for serious, yellow for moderate. Hover overlays show remediation tooltips.
DevTools Panel
A full split-view panel inside Chrome DevTools — violations list, detail view with remediation hints, element picker, and impact filter chips.
Keyboard Navigation
Navigate violations with ↑↓ arrow keys, jump to page elements with ← →, and expand detail sections — full zero-mouse workflow.
Export JSON
Download the complete axe-core results as structured JSON for CI pipelines, issue trackers, or formal accessibility audits.
Workflow
From install to insights in seconds
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Install the extension
Add a11y DevTools to Chrome from the Web Store. One click, no account needed.
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Open any webpage
Navigate to any live site or localhost. Works on any HTTP/HTTPS page.
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Run a scan
Click the toolbar popup or open DevTools → a11y panel and hit "Run Quick Scan".
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Fix violations
Highlighted elements, descriptions, and fix guidance. Rescan instantly to verify.
Scoring
Weighted impact scoring
Every violation is penalized based on how severely it impacts people with disabilities. The score starts at 100 and deducts points per violating node.
Critical
Blocks screen reader users entirely
−10 / node
Serious
Significantly impairs assistive technology
−7 / node
Moderate
Creates barriers but has workarounds
−4 / node
Minor
Minor annoyances and best-practice issues
−2 / node
Pass
Rule fully compliant — no penalty
+0
| Grade | Score | Interpretation |
|---|---|---|
| A | 90 – 100 | Excellent — production ready |
| B | 75 – 89 | Good — minor fixes needed |
| C | 50 – 74 | Fair — several issues to address |
| D | 25 – 49 | Poor — significant barriers present |
| F | 0 – 24 | Critical — major remediation required |
Disclaimer: This is an independent open-source project.
Not affiliated with, endorsed by, or associated with Deque Systems or their products.
Standards
WCAG compliance coverage
Comprehensive rule coverage across all applicable guidelines.
WCAG 2.1 AA
Web Content Accessibility Guidelines
Full coverage of perceivable, operable, understandable, and robust success criteria at the AA conformance level.
WCAG 2.2 AA
Latest Guidelines (2023)
Includes new 2.2 criteria: focus appearance, dragging movements, target size minimum, and consistent help patterns.
Best Practices
Beyond Strict Compliance
Additional axe-core best-practice rules that improve UX for assistive technology users even when not strictly required by WCAG.
Free · Open Source · No account
Start testing
Start testing
accessibility today
Zero configuration. Everything runs locally — no data is sent to any external server.
Requires Chrome 109+. Works on any HTTP/HTTPS page including localhost.