The most common WCAG failures

The six most common WCAG failures are low contrast, missing alternative text, form fields with no label, empty links, empty buttons and a missing document language. In the February 2026 WebAIM Million sample they account for 96% of detected errors, and 95.9% of home pages had at least one WCAG 2 failure.

Contrast is measured, not judged

Success criterion 1.4.3 asks for a ratio of 4.5:1 for normal text and 3:1 for large text; 83.9% of home pages miss it. The fix is not in the single component, it is in the theme tokens. Correct the background and foreground pair once and recompute contrast, instead of chasing individual cases. The measured palette of the catalogue is in palette and measured contrast.

Alt text, labels, accessible names

• Images (1.1.1): informative alt text describes what the image does; a decorative image carries alt="" and is never announced.
• Form fields (3.3.2): every input has a <label for> or an accessible name; a placeholder is not a label and disappears once typing starts.
• Icon buttons (4.1.2): the name comes from visible text or aria-label. An SVG inside the button stays decorative with aria-hidden="true".

Empty links and empty buttons

46.3% of pages have at least one link with no accessible name and 30.6% at least one empty button. The usual case is a social icon holding only an SVG: the name is missing, the control stays reachable by keyboard and the screen reader announces “link”. Do not add aria-label when visible text already exists: it creates a mismatch between what people see and what they hear.

The document language

13.5% of pages declare no language. You need one attribute on the root element, <html lang="it">, plus a different lang on blocks written in another language. Without it the screen reader applies the wrong phonetics and the page becomes unintelligible even when the text is right.

How to find them quickly

Pa11y is open source under the LGPL-3.0 licence and applies WCAG rules to the rendered page. The command below checks a whole sitemap and prints one line per URL.

npx --yes pa11y-ci --sitemap https://example.com/sitemap.xml --standard WCAG2AA

Then run the check no tool replaces: tab through the page, press Enter and Space on the first control, and listen to the announcement with VoiceOver or NVDA. A contrast failure is visible to the tool, but a name that describes the wrong thing is only heard by the person listening.

The EneUI catalogue

EneUI indexes the accessibility category and the form components. A verified record is Origin UI's dialog, with an MIT licence declared upstream: it depends on @radix-ui/react-dialog, so the name, the focus handling and the Escape close come from the primitive. Checked on 1 November 2026 against 111,985 components.

The limitation

An automated audit measures what can be decided without context. It cannot tell useful alt text from useless alt text, it cannot see whether focus returns to the right place after a modal closes, and it cannot hear a wrong announcement. The count of 56.1 errors per page is therefore a lower bound: no tool proves conformance.

Where to continue

The full process is in how to run an accessibility audit; the operational checklist for components is in accessible React components. To decide which attributes actually help, read the comparison of headless primitives in Radix, Base UI and React Aria.