WAVE

WAVE — Web Accessibility Evaluation Tool — is the free accessibility checker from WebAIM (Web Accessibility In Mind), an accessibility nonprofit based at Utah State University. WAVE has been continuously developed since 2001, making it the longest-running accessibility- audit tool on the web.

What WAVE does

WAVE runs in two main modes:

1. wave.webaim.org — a hosted scanner. Paste a URL; WAVE fetches the page and reports findings in a side-by-side view (live page on the left, annotations on the right).
2. WAVE browser extension — a Chrome/Edge/Firefox extension that evaluates the currently-viewed page in place. The page is annotated with overlay icons indicating errors, alerts, structural elements, ARIA usage, and contrast.

Both modes produce roughly the same output: a categorised list of findings overlaid on the live page so the auditor can see exactly where each issue lives.

What WAVE catches

WAVE’s checks overlap heavily with axe-core’s, but the presentation is different — WAVE is built for human auditors doing visual review, not for CI integration. Findings include:

• Errors — accessibility failures (missing alt, empty buttons, missing labels, low contrast, broken ARIA references).
• Contrast errors — colour-contrast violations with WAVE’s own detection (broadly aligned with WCAG’s algorithm).
• Alerts — likely issues that need human judgment (suspicious alt text, long alt text, possible heading skips).
• Features — accessibility-positive findings (linked images with alt, form labels properly associated, language declarations) so the auditor can confirm what’s working.
• Structural elements — visualised landmarks, headings, lists, tables. Useful for verifying the page’s structure matches the intent.
• ARIA — every ARIA attribute on the page, surfaced for review.

When WAVE beats axe-core

For manual auditing, WAVE’s visual overlay is much faster than axe-core’s tree view. A trained auditor can scan a WAVE-annotated page in seconds and identify the issues that need attention. axe-core’s output, by contrast, is optimised for programmatic consumption.

For CI integration, axe-core wins decisively. WAVE has no command-line interface and no CI-friendly output format.

The practical combination most accessibility programmes adopt:

• CI: axe-core (and/or Lighthouse) blocking pull requests on new violations.
• Manual review: WAVE for visual auditing during release reviews, spot-checks, and ad-hoc investigation.

What WAVE doesn’t catch

The same limitations that apply to all automated tools apply to WAVE:

• It catches missing alt, but not bad alt.
• It catches missing labels, but not misleading labels.
• It catches structural issues (heading-level skips), but not conceptual issues (page outline that doesn’t match the content).
• It can’t test keyboard navigation, focus order, or actual screen-reader behaviour.

The 30-40% automated-detection ceiling applies. WAVE is excellent at the part of accessibility automation that can be automated.

WebAIM’s broader contribution

WebAIM publishes several reference documents that complement WAVE:

• The WebAIM Million — annual analysis of accessibility on the top million home pages, run via WAVE-based testing. Reports consistently show >95% of home pages have detectable accessibility issues.
• The WebAIM Screen Reader User Survey — biennial demographic survey of screen-reader users, the most-cited source on screen- reader market share, browser pairing, and assistive-tech preferences.
• A library of tutorials on alt text, table structure, PDF accessibility, captioning, and many other topics — written practically rather than as standards-translation work.