Axe
The world's leading accessibility testing engine. Automated WCAG compliance checking for web, mobile, and documents.
Overview
Axe, created by Deque Systems, is the most widely used accessibility testing engine in the world. It powers accessibility testing in browser developer tools, CI pipelines, and automation frameworks. Axe tests web pages against the Web Content Accessibility Guidelines (WCAG) 2.1 and 2.2, flagging issues like missing alt text, incorrect heading hierarchy, colour contrast failures, and keyboard navigation problems.
Axe is available as a browser extension (free), a JavaScript library for automation integration, and a comprehensive enterprise platform (Axe DevTools). It is the standard tool for automated accessibility testing.
What it's used for
Axe is essential for:
- WCAG compliance testing: Automated checks for accessibility standards compliance.
- CI/CD accessibility gates: Block deployments that introduce accessibility regressions.
- Developer accessibility awareness: Browser extension provides instant feedback during development.
- Legal compliance: Many jurisdictions (including NZ) require digital accessibility under human rights legislation.
Pros & Cons
Pros
- Industry standard — used by Google, Microsoft, and government agencies
- Low false-positive rate compared to other accessibility tools
- Integrates with Playwright, Cypress, Selenium, and Jest
- Free browser extension for quick checks
- Comprehensive rule set covering WCAG 2.1 and 2.2
Cons
- Only catches ~30% of accessibility issues — manual testing still required
- Enterprise platform (Axe DevTools) is expensive
- Some advanced WCAG criteria require manual verification
- Can miss context-specific accessibility problems
- Requires understanding of accessibility to interpret results
Platforms & Integrations
Axe runs on Windows, macOS, and Linux. The browser extension works in Chrome, Firefox, and Edge. The JavaScript library integrates with any Node.js test framework.
Pricing
| Tier | Cost | Includes |
|---|---|---|
| Axe DevTools Browser Extension | Free | Basic accessibility scanning in browser |
| Axe DevTools Pro | $40/user/mo | Advanced rules, guided testing, reporting |
| Axe DevTools Enterprise | Custom | CI integration, dashboard, governance, support |
NZ Context
Axe is the recommended accessibility testing tool in NZ government digital standards. The Digital Service Standards and NZ Accessibility Guidelines reference automated testing tools like Axe. NZ organisations receiving government funding or serving the public are increasingly required to meet WCAG 2.1 AA standards. For NZ web developers and testers, Axe is an essential tool.
Alternatives
- Lighthouse — Built into Chrome DevTools. Free but less comprehensive.
- WAVE (WebAIM) — Free browser extension with visual feedback.
- Pa11y — Command-line accessibility testing. Good for CI integration.