HTML Accessibility Checker

Automation finds about a third of the problems

Studies of automated accessibility tools consistently put their coverage at roughly 30 to 40 percent of WCAG failures. They reliably catch missing alt attributes, unlabelled form controls, insufficient colour contrast, missing document language and invalid ARIA. They cannot judge whether alt text is accurate, whether a heading structure reflects the content, whether focus order makes sense, or whether an error message is comprehensible. A clean automated report is the beginning of an audit, not the end of one.

The failures that dominate real scans

Annual surveys of the top million homepages find the same list every year: low-contrast text, missing alt attributes, empty links, missing form labels, empty buttons and missing document language. Six issues account for the large majority of detected failures, and every one is straightforward to fix. Most sites do not need sophisticated remediation; they need these six done.

Native elements before ARIA

The first rule of ARIA is not to use ARIA when a native element does the job. A <button> is focusable, keyboard-operable and announced correctly with no attributes at all; a <div role="button"> needs tabindex, key handlers for Enter and Space, and state management, and usually gets one of them wrong. Incorrect ARIA is measurably worse than none, because it overrides what assistive technology would otherwise infer correctly.

Alt text is a judgement call

A checker confirms the attribute exists. Whether "image1.jpg" or "click here" is useful, it cannot say. Decorative images should carry an empty alt attribute so screen readers skip them — omitting the attribute entirely causes some readers to announce the filename instead. Informative images need a description of the information, not the picture, and the right text depends on why the image is there.

Keyboard access is where automation stops

Every interactive element must be reachable and operable by keyboard, with a visible focus indicator, in an order that matches the visual layout. Modals must trap focus and return it on close. Custom dropdowns and date pickers are where this breaks most often. Tabbing through a page takes two minutes and finds more real problems than any scanner.

Legal exposure is real and rising

Web accessibility lawsuits have grown steadily year on year, overwhelmingly citing WCAG 2.1 Level AA. The European Accessibility Act applies from June 2025 to a wide range of digital services. Beyond compliance, roughly one in six people has a disability, and an inaccessible site excludes them from transacting at all.