axe-core

Name: axe-core
Author: Deque Systems

The open-source accessibility rules engine almost every other tool is built on.

AccessibilityOpen sourceSelf-hostable

What it is

axe-core is Deque's JavaScript library that evaluates a rendered page against WCAG rules and returns violations with the element, rule and remediation guidance. It is deliberately tuned for zero false positives, and it powers Lighthouse, Chrome DevTools, Playwright's accessibility checks and most commercial scanners.

Best for

Any team that wants accessibility checks inside their existing automated tests.

Where it is strong

Effectively zero false positives, which is why it became the industry default.
Integrates into any existing test suite in a few lines.
Free, actively maintained, and aligned with WCAG updates.

Where it falls short

Automated rules detect roughly a third of WCAG issues — the rest need human testing.
A library, not a workflow: no dashboards, tracking or reporting.
Only evaluates the DOM state it is given, so dynamic states need explicit test coverage.