RE: Clarification on AI-Based Accessibility Overlays and WCAG Conformance

If an overlay was able to provide an accessible conforming version of a website, that would be acceptable. In principle, an overlay could address some non-conformances, but it depends on what they are. You certainly cannot claim that an overlay will address all the non-conformances on any website, even though some vendors make this claim. In my experience, the overlays on websites we have tested have never been able to address any of the WCAG non-conformances we have reported.

Overlays may get better as AI improves, but I doubt that they will ever be able to correctly address more than a small proportion of WCAG non-conformances.

If you want to claim conformance, you need to do a full WCAG audit, identify the non-conformances, then determine whether the overlay can address them all. If the website is in really good shape, maybe the overlay can do that. But if that's the case, you may as well fix the non-conformances. If the website is in bad shape, the overlay won't help. Either way, you're better off not using the overlay.

WCAG already accommodates overlays. Whether or not the underlying code remains unchanged is irrelevant - all that matters is whether the success criteria are met. My recommendation is to forget about overlays, now and forever.

Steve Green
Managing Director
Test Partners Ltd

From: Mario Toscano <mario.toscano@spindox.it>
Sent: 28 April 2025 15:54
To: w3c-wai-ig@w3.org
Subject: Clarification on AI-Based Accessibility Overlays and WCAG Conformance

Dear all,

I am reaching out to ask for clarification regarding the use of AI-based overlay tools for web accessibility.

Many current solutions on the market claim to make a website accessible through overlay that adds functionalities such as:


  *   text resizing,
  *   color contrast adjustments,
  *   screen reader support,
  *   keyboard navigation,
  *   and simulation of assistive technologies.

However, these tools do not modify the original source code or semantic structure of the website.

My questions are:


  1.  According to WCAG 2.1 or 2.2, can a website that relies solely on such AI overlay tools be considered conformant at Level AA?
  2.  Is the use of such AI-based overlays sufficient for public or private and private organizations to legally declare conformance with WCAG standards?
  3.  Will future versions of WCAG (e.g., WCAG 3.0) possibly include such overlays as acceptable methods of achieving compliance, even if the underlying code remains unchanged?

Thank you very much for your tim.

Best regards


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Mario Toscano
SW QA Deputy Director

Mobile: +39 340.9569893
E-mail: mario.toscano@spindox.it<mailto:mario.toscano@spindox.it>
Linkedin: https://www.linkedin.com/in/mariotoscano1/

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