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axe-core

github.com

Free plan WebAPIBrowser extension
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Spec score 8.5 #29 of 169 in Accessibility Testing Software

What it is

axe-core is a free, open-source accessibility testing engine for websites and other HTML-based interfaces. It is designed to run beside functional tests in unit, integration, browser, and other testing environments. Its rules cover WCAG 2.0, 2.1, and 2.2 at A, AA, and AAA levels, along with additional best practices. Deque says automated checks find an average of 57% of WCAG issues, while uncertain findings are marked for manual review. Installation is documented through npm or pnpm, with tests calling the axe.run() API. The API lists Microsoft Edge, Google Chrome, Mozilla Firefox, and Apple Safari; Internet Explorer 11 is deprecated. Chrome and Firefox are tested on every pull request. JSDOM support is limited, and color-contrast checks do not work there. axe-core uses the Mozilla Public License 2.0. Security updates are available for minor lines up to 18 months old. Vulnerabilities are requested by email, with a stated 24-business-hour response and no bug bounty.

Spec sheet

Purpose
axe-core is an accessibility testing engine for websites and other HTML-based user interfaces that can run alongside functional tests.Read 11 Oct 2026 · github.com
Free plan
YesRead 21 Sep 2026 · github.com
License
axe-core is distributed under the Mozilla Public License, version 2.0.Read 11 Oct 2026 · github.com
Headquarters
Herndon, Virginia, USARead 28 Sep 2026 · github.com
Founded
2015Read 28 Sep 2026 · github.com
API access
YesRead 21 Sep 2026 · github.com
Automated coverage
Deque says axe-core finds an average of 57% of WCAG issues automatically and marks uncertain results for manual review.Read 11 Oct 2026 · github.com
Browser testing limits
Only Chrome and Firefox are tested on every pull request, and JSDOM support is limited, with color-contrast known not to work there.Read 11 Oct 2026 · github.com
CI/CD integration
YesRead 21 Sep 2026 · github.com
Integration
The engine is designed to integrate with existing unit, integration, browser and other functional test environments.Read 11 Oct 2026 · github.com
Maintainer
Deque says it released axe-core in 2015 and identifies Deque Systems, Inc. as its maker.Read 11 Oct 2026 · deque.com
Maker headquarters
Deque Systems, Inc. lists its address as 13800 Coppermine Road, Herndon, Virginia 20171.Read 11 Oct 2026 · deque.com
Package
The README shows installation through npm or pnpm and use of the axe.run() API in tests.Read 11 Oct 2026 · github.com
Scan scope
pageRead 21 Sep 2026 · github.com
Security updates
Deque says security updates are available for minor version lines up to 18 months old.Read 11 Oct 2026 · github.com
Standards
Its rules cover WCAG 2.0, 2.1 and 2.2 at levels A, AA and AAA, plus additional best practices.Read 11 Oct 2026 · github.com
Supported browsers
The API lists Microsoft Edge, Google Chrome, Mozilla Firefox and Apple Safari as supported; Internet Explorer 11 is deprecated.Read 11 Oct 2026 · github.com
Vulnerability reporting
Deque asks researchers to report vulnerabilities by email rather than through public GitHub issues and says it responds within 24 business hours; it has no bug bounty program.Read 11 Oct 2026 · github.com
WCAG version
wcag 2.2Read 21 Sep 2026 · github.com

Plans and prices

axe-core Free Open-source accessibility testing engine · MPL-2.0 license Read 11 Oct 2026 · github.com

Every axe-core plan and price →

Strong points and limits

Strong points

  • Covers WCAG 2.0 through 2.2
  • Integrates with existing test environments
  • npm and pnpm installation
  • API supports major modern browsers
  • Free under MPL-2.0

Limits

  • Automated checks do not find every issue
  • JSDOM support is limited
  • Color contrast does not work in JSDOM
  • Internet Explorer 11 is deprecated

Who it suits

axe-core suits developers integrating automated accessibility checks into web application and functional test suites.

Verdict

axe-core provides standards-based automated accessibility checks that can be embedded in existing tests. Manual review remains necessary for uncertain and uncovered issues.

Where Specifiction places it

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