type: service
status: active
timestamp: 2026-06-20
tags: [a11y, accessibility, axe, ci, primary]

axe-core

Industry-standard a11y rule engine; @axe-core/playwright in CI

axe-core

Role

Static-rule a11y engine — runs Deque’s WCAG 2.1 / 2.2 ruleset against rendered pages and emits violations. The family runs @axe-core/playwright in every site’s PR CI as one of the three a11y tools; PR fails on any new violation.

Free tier

Unlimited — MPL-2.0 open-source npm package
No account, no API key, no rate limit
Bundles the Deque rule catalog locally; no network call at run time

Card / subscription required?

NO. OSS — installed via pnpm add -D @axe-core/playwright.

How CI consumes it

// tests/a11y.spec.ts
import { test, expect } from '@playwright/test';
import AxeBuilder from '@axe-core/playwright';

test.describe('a11y (axe)', () => {
  for (const path of ['/', '/about', '/support']) {
    test(`no violations on ${path}`, async ({ page }) => {
      await page.goto(path);
      const results = await new AxeBuilder({ page })
        .withTags(['wcag2a', 'wcag2aa', 'wcag21a', 'wcag21aa'])
        .analyze();
      expect(results.violations).toEqual([]);
    });
  }
});

Runs alongside the Pa11y and Lighthouse CI jobs in the same PR.

What it catches

Missing labels (<input>, <button>, <a> without text)
Insufficient color contrast (4.5:1 for body, 3:1 for large text)
Missing landmarks
Non-unique IDs
Missing alt text
ARIA misuse
Heading hierarchy violations

Alternatives

Pa11y — different ruleset (HTML_CodeSniffer or axe); we run alongside, not instead.
Lighthouse CI — also includes axe rules but scoring-focused; we run alongside.
WAVE API — paid past free tier.
accessibility-checker (IBM) — alternative ruleset, smaller community.

Swap cost

Medium — axe is the de-facto a11y rule engine; Pa11y can run axe as its backend, so dropping @axe-core/playwright and pointing Pa11y at axe-runner keeps coverage. Test files would need rewriting.

Why this is our pick

The industry-standard ruleset — Deque maintains it, Microsoft and Google contribute. Playwright integration runs in the existing browser context (no extra infrastructure). Free, OSS, unlimited. Pairs with Pa11y (different ruleset) and Lighthouse CI (scoring) for three-tool a11y coverage.

Cross-refs

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