Comparisons & definitions
axe-core vs WAVE vs Lighthouse: what automated accessibility checkers actually catch
The question
You've been told to "run an accessibility checker." Three free names come up constantly — axe-core, WAVE, and Lighthouse. What does each actually do, and what does NONE of them do?
What is true
- axe-core (Deque) is the open-source rules engine most other tools embed. It runs in the browser or in test pipelines, reports violations mapped to WCAG criteria with the offending selector, and is designed to avoid false positives — if axe flags it, it's almost certainly real. That conservatism is also its limit: it stays silent on things it can't determine mechanically.
- WAVE (WebAIM) is the visual one: it overlays icons on the page itself, which makes it the best teaching tool — you SEE where the unlabeled field or missing alt sits. Same fundamental class of checks, presented for humans rather than pipelines.
- Lighthouse (in Chrome DevTools) includes an accessibility score — which is actually powered by a subset of axe-core rules. Its number is convenient and widely misread: a 100 accessibility score means "passed the automated subset," not "accessible," and Lighthouse says so itself.
- What none of them catch: whether the alt text is meaningful (not just present), whether keyboard focus order makes sense, whether a screen-reader user can complete your checkout, whether captions are accurate. Estimates of how much of WCAG automated tools can cover vary and we won't invent a percentage — the honest statement is: automated checks find the mechanical failures reliably and the judgment failures never.
So which one?
Use axe-core (or anything embedding it) for repeatable checks and CI; WAVE to understand and explain findings; Lighthouse for a quick pulse — never as a compliance claim. And for anything legal, pair the automated pass with human judgment on the key flows.
The honest shortcut
SiteComply's audit runs the automated pass for you — axe-core signals plus consent posture, broken links and SEO basics — with every finding linked to the exact page state observed, and it never claims the automated pass is more than it is. That last sentence is the whole difference between an audit and a badge.