Free WCAG 2.1 AA checker in 30 seconds.

The Web Content Accessibility Guidelines version 2.1 are the technical standard United States courts cite when they interpret the Americans with Disabilities Act in the context of websites. The guidelines are organized into four principles, often shortened to POUR.

Perceivable means the content can be presented in ways people can sense. Image alternative text, captions on video, sufficient color contrast between text and background, and a content order that still makes sense when CSS is turned off all fall here.

Operable means all functionality is available from a keyboard, users can pause moving content, and links and buttons have a clear focus state. Most demand letters our customers receive cite an operable criterion at least once.

Understandable covers readable language, predictable navigation, and form inputs that explain themselves when something goes wrong.

Robust covers valid HTML, name-role-value information for custom widgets, and the contract every screen reader and assistive tool relies on.

Level AA is the conformance bar most US regulators reference. It covers everything in Level A plus the additional contrast, resize, and orientation rules. Our full methodology page lists the exact criteria we test against, with examples: read how the scan runs end to end.

When you submit a URL above, we load the page in a real headless Chromium browser. Not a static HTML parser, not an HTTP fetcher, a real browser that executes JavaScript, applies CSS, and lets the page hydrate exactly the way a Chrome visitor would see it. That matters because most modern websites paint critical navigation, modals, and product information through JavaScript after the initial HTML response arrives.

Once the page settles, we inject an industry-standard rule engine into the DOM and traverse every element on the page. The engine evaluates roughly ninety distinct rules tied directly to specific WCAG criteria. Some rules check structural facts: does this image have alternative text, does this form input have an accessible name, does this button reachable by keyboard. Others run measurements: is the contrast ratio between this text and its background high enough for WCAG 2.1 AA, does this heading level skip a step in the document outline.

Each violation comes back with three pieces of information you can act on: the WCAG criterion that was failed, the CSS selector that identifies the element in the page, and a plain-English suggestion for remediation. We bundle those into a score, group identical rule failures into one row, and email you the result. The dated audit-trail PDF is a signed-in feature; the free checker sends the findings themselves.

Automation is not magic. Roughly thirty to forty percent of WCAG criteria are testable by a machine. The rest require human judgment: is this alt text accurate, does this form label actually describe the field, is this animation respectful of motion preferences. Our FAQ explains where automated testing stops and a manual review begins.

After thousands of scans across e-commerce, hospitality, legal, and healthcare sites, the same handful of findings dominate the top of nearly every report.

1. color-contrast: body copy, link colors, and button states fail the WCAG 2.1 AA contrast ratio of 4.5:1 on regular text or 3:1 on large text. Often a brand color the designer loved that the guideline does not.
2. image-alt: a product photo, hero image, or icon button rendered without meaningful alternative text. Screen readers either announce nothing or read the file name out loud.
3. link-name: a link wraps an icon or empty span with no accessible label. Users hear "link" and nothing else.
4. label: a form input has a visual placeholder but no programmatic label. The field looks labelled to sighted users; assistive tech sees an unnamed input.
5. aria-required-attr: a custom widget uses an ARIA role but is missing the attributes that role expects. Frequently shows up in slick custom dropdowns, tabs, and carousels.

The same patterns dominate the industry breakdowns we publish on the Invoset blog, including dedicated checklists for restaurants, dental practices, law firms, hotels, and Shopify stores.

The free checker tests one URL. That is plenty for a quick gut check on your homepage, a landing page you are about to launch, or a competitor's site you want to size up. For anything more, you usually need a wider scope.

Whole sites. An ADA demand letter rarely names a single page. Plaintiffs and their counsel cite the experience across the site, including menus, checkout, location pages, and PDF documents. A monitored Invoset subscription crawls the sitemap on a schedule and dates every report. See the plan comparison for page limits and cadence per tier.

Authenticated pages. The free checker cannot get past a login wall. The same is true for any automated tool that has not been given credentials. Authenticated crawl is on our roadmap for the Business plan.

Mobile apps. Native iOS and Android apps are not covered by the WCAG guidelines directly; they follow platform-specific accessibility frameworks. The web view of your app, if you have one, can still be scanned.

Procurement. When a federal contractor, hospital, or university asks for a VPAT or a Section 508 conformance report, an automated scan is one input, never the whole document. Pair it with a CPACC manual review. Our published VPAT shows the format procurement teams expect.