Guide

Do accessibility overlays work?

Not for the thing they are sold for. An overlay can change how a page looks. It cannot repair the markup underneath, it cannot make the judgements accessibility requires, and buying one has not kept sites out of court.

What an overlay actually is

An overlay is a script you add to your pages. It runs in the visitor’s browser after the page loads and does two kinds of thing:

• A settings widget. A button that opens a panel offering larger text, higher contrast, a different font, a reading guide, and similar controls.
• Automatic repairs. Scripts that try to guess missing information, such as generating alt text for images or inferring an ARIA role for an unlabelled control.

Why the settings widget is mostly redundant

Every browser already has zoom. Operating systems already have high contrast modes, text scaling, and reading tools. People who need those settings have already configured them, system-wide, in the way they prefer. A per-site widget asks them to find and re-do that work on your site alone.

Worse, some overlays interfere with the assistive technology the visitor is already running, because two systems are now trying to manage the same page.

Why the automatic repairs cannot work

Accessibility is largely about meaning, and the meaning is not in the page for a script to find.

• A generated alt text can say “a person holding a phone”. It cannot know the image is a diagram of your pricing tiers.
• A script can add a label to a field. It cannot know whether the field wants a delivery address or a billing address.
• A script can detect a low contrast pair. It cannot decide which of your brand colours you are willing to change.
• Nothing running in the browser can caption a video, or check that existing captions are accurate.

These are the same limits every automated tool has, ours included. The difference is that we say so, and an overlay is sold as though the limit does not exist.

What the FTC said

In January 2025 the Federal Trade Commission announced an action against accessiBe, one of the largest overlay vendors. The complaint concerned claims that its product could make any website compliant with WCAG, and the promotion of reviews from parties with an undisclosed financial relationship. The matter was settled with a monetary judgment and restrictions on future claims.

The relevant part for you is not the money. It is that a federal regulator examined the central marketing claim of this product category and found it did not hold.

We read every sentence on our own site against that complaint, and cut anything that would not survive the same reading. The scope of our claims.

What the lawsuit numbers show

Firms that track US web accessibility litigation have consistently reported that a substantial share of the sites sued had an overlay installed at the time of the claim, running into the hundreds of cases per year. The overlay was not a defence, because the underlying barriers were still there.

This is the practical test. If the product worked, the sites running it would not keep appearing on those lists.

Are overlays ever worth having?

A widget that offers a few display preferences is not harmful in itself, if it does not fight the visitor’s own assistive technology. Judge it as a small convenience feature, priced like one. The mistake is counting it as remediation, or as protection.

What to do instead

1. Find the real failures. A scan does the part a machine can do, in minutes.
2. Fix them in the source, where the fix is permanent and helps every visitor.
3. Do the human checks. Keyboard, screen reader, captions, error messages. The report names each one.
4. Record what you did. That record is what a claim actually meets.

Sources: FTC press release and complaint concerning accessiBe, January 2025; published annual digital accessibility litigation reports. Figures change year to year; check the current report before quoting a number.