Do accessibility overlays meet the law?

No. No W3C standard, and not Brazil's NBR 17225 either, recognizes an overlay as a way to meet accessibility criteria. WCAG conformance is measured on the page as delivered, criterion by criterion, and the W3C itself says automated tools cannot determine whether a site is accessible; part of the evaluation requires human judgment. Disability organizations and accessibility professionals state publicly that overlays do not make a site accessible or legally compliant. What fixes accessibility is changing the code and the content, and testing with people.

This article covers WCAG 2.2, ABNT NBR 17225:2025 (Brazil's web accessibility standard) and the Lei Brasileira de Inclusão (LBI, Brazil's Inclusion Law), with information checked in October 2026. It explains the standards; it is not legal advice.

What an accessibility overlay is

An overlay is a third-party script, almost always JavaScript, that a site installs with one line of code and that acts on the page in the visitor's browser. There is no formal definition of the term, according to a document from a W3C community group on the subject (Overlay Applications in Web Accessibility). Products sold as overlays usually combine two things:

• A preferences panel, opened by a fixed button in a corner of the screen, with options such as enlarging the font, changing contrast, increasing spacing or highlighting links.

• Automatic repair: the script analyzes the code when the page loads and tries to fix problems, such as images without alternative text, fields without labels or missing ARIA attributes.

Some products add reports or assistive technology detection. The sales pitch ranges from "more accessibility" to "legal compliance in minutes".

What the W3C says

As of the access date, the W3C and its Web Accessibility Initiative (WAI) had not published an official recommendation or guidance dedicated to overlays. What exists are three points that answer the question indirectly.

Conformance applies to the whole page and to every criterion

To claim level AA, the page must meet every A and AA criterion, without excluding parts, in every screen variation, and in every step of a process such as checkout (WCAG 2.2, 5.2). A script that fixes some of the problems leaves the site non-conforming as long as a failure remains in any criterion.

Automated tools do not decide whether a site is accessible

On its page about evaluation tools, the W3C says tools cannot check every aspect of accessibility, that human judgment is required and that they can only assist in determining accessibility (Selecting Web Accessibility Evaluation Tools). The W3C evaluation overview adds that no tool alone can determine whether a site meets the standards and recommends including people with disabilities in testing (Evaluating Web Accessibility Overview). An automatic repair overlay relies on the same kind of automated analysis, only applied on the fly, with no review.

A W3C community group studied the subject

The A11yEdge Community Group published the draft "Overlay Applications in Web Accessibility". Community group documents are not W3C standards or recommendations, and this one is an exploratory draft. It is more balanced than most of the debate: it lists possible uses, such as fixing defects in libraries shared by many sites, and problems, such as excessive screen reader announcements, broken focus order, preferences that duplicate the operating system's, and disability detection without consent. And it says overlays do not replace human expertise and oversight in the remediation process.

What professionals and organizations say

Two public statements are cited most often. Neither is a law or a standard; they are positions of people who work in accessibility or represent people with disabilities.

• The Overlay Fact Sheet is a text signed by accessibility professionals, developers, lawyers and users with disabilities; on the access date, the list had more than a thousand signatures. It states that overlays do not achieve full WCAG conformance, that preference panels repeat features users already have on their devices, that automatic repair of alternative text, labels, keyboard access and focus is unreliable, and that some products detect the use of assistive technology, which exposes the visitor's disability. It recommends fixing problems at the source, in the code.

• The European Disability Forum (EDF) and the International Association of Accessibility Professionals (IAAP) published a joint statement on May 17, 2023. It says overlays do not make a site accessible or compliant with European accessibility legislation, that they are not an acceptable substitute for fixing the site, that they can interfere with assistive technologies and that accessibility is the responsibility of the site owner, not the user.

Limits of an overlay

Privacy

Overlays that detect a screen reader or other assistive technology can infer that the visitor has a disability. Brazil's LGPD (Lei Geral de Proteção de Dados, Brazil's data protection law, Law 13,709/2018, art. 5, II) classifies "data concerning health", among others, as sensitive personal data (Law 13,709/2018). Whether that inference counts as data concerning health is an open question: we found no position from the ANPD (Brazil's data protection authority) on the subject, and the answer depends on a legal analysis of the case. In practice, anyone who already uses or is considering an overlay should know what data the script collects, where it sends it and on what legal basis.

The accessiBe case at the FTC, in the United States

On April 22, 2025, the FTC, the US consumer protection agency, approved the final order against accessiBe, the vendor of the accessWidget overlay (FTC press release). According to the FTC:

• the company advertised that accessWidget could make any website WCAG compliant, and the FTC alleged that the product did not do so for all of its customers' websites;

• the company also presented third-party articles and reviews as if they were independent opinions;

• the order requires a $1 million payment and bars the company from claiming that its automated products can make any website WCAG compliant, or keep it compliant, without evidence to support the claim;

• the vote was 3 to 0.

The case is about deceptive advertising under US consumer protection law. It is not a ruling on Brazilian law or on the accessibility of any specific website. It does show, however, that the "automatic compliance" promise has already been challenged by a public agency on the facts.

And in Brazil

Article 63 of the LBI makes accessibility mandatory on the websites of companies with headquarters or commercial representation in the country and of government bodies, in accordance with internationally adopted best practices and guidelines (Law 13,146/2015). The law does not mention overlays or widgets.

ABNT NBR 17225:2025 follows the WCAG 2.2 criteria, and regular conformance, which the standard aligns with level AA, requires meeting every requirement (ABNT NBR 17225:2025, section 4). The standard does not mention overlays either. In Annex A, on third-party content, it notes that the accessibility of content the author does not control cannot be guaranteed and recommends choosing sources that follow good practices. A third-party script that changes the page falls into that category.

What the law requires, and of whom, is in the main guide of this series, LBI and NBR 17225: what Brazilian law requires of a website.

What actually fixes accessibility

1. Find the problems with an automated tool and with manual tests: keyboard-only navigation, screen reader, 200% zoom, contrast. The WCAG 2.2 level AA guide shows how to test the new criteria.

2. Fix them in the code and content: semantic HTML, alternative text written by someone who knows the image, clear labels and error messages, contrast, components that work by keyboard. The accessible forms guide has HTML examples.

3. Fix them at the shared source: theme, design system or component library. A fix there applies to every page that uses that component.

4. Test with people with disabilities, as the W3C recommends.

5. Ask third-party content vendors (chat, payments, video, maps) for accessibility, as NBR 17225 suggests.

6. Check again after every change to the site, because new content and theme updates bring new problems.

One caveat: the preferences panel, by itself, is not the problem. If a site wants to offer an extra adjustment the browser does not have, nothing prevents it, as long as the panel is accessible, does not interfere with assistive technology and is not presented as proof of conformance. The recommendation to remove the overlay does not apply to that case; it applies to sites that rely on it instead of fixing the code.

How to check your site

The WebVyze free check analyzes the home page, with no sign-up, and points out accessibility risks under the law. WebVyze is not an overlay: it only reads public pages and never changes the site. On the paid plans (pricing), each problem becomes an issue with the law, the criterion, the evidence and a fix guide, and is marked as resolved only after WebVyze checks again. Some WCAG criteria still require human review, as described above.