I use assistive tech – here’s why accessibility overlays don’t work

As an assistive technology user, I see a recurring trend: websites deploying plugins that offer superficial accessibility controls like options to adjust font size, toggle high contrast themes, and even text-to-speech options. While these tools can be helpful to some users, they often exist to compensate for fundamental accessibility failures.

For example, if a website isn’t built to handle responsive resizing, increasing text size using the browser’s built-in zoom may cause content to overflow, become truncated, or disappear entirely. These aren’t edge cases - they’re usability failures that can and should be avoided through thoughtful, standards-based design.

Accessibility shouldn’t depend on overlays

Websites must be built to support user preferences and assistive technologies from the ground up - not rely on overlays or browser hacks to patch issues. Native OS settings and browser features (like text resizing or high-contrast modes) are far more robust and consistent than any plugin or widget.

With the introduction of the European Accessibility Act, the spotlight on digital inclusivity has intensified. In response, some companies look for shortcuts - ways to solve accessibility through automation. Enter: accessibility overlays.

What are accessibility overlays?

Overlays are third-party tools added to a website to modify the presentation layer of a website in real time. They add widgets that offer features like:

• Contrast toggles
• Text resizing
• Supposed ‘screen reader modes’ 

Behind the scenes, these tools might dynamically inject ARIA attributes, manipulate the DOM structure, or attempt to retrofit keyboard support - all without changing the actual source code.

Popular accessibility overlays like AccessiBe, AudioEye, and UserWay have promised a seamless path to compliance*: insert a script, and your site is compliant with WCAG, ADA, and other standards.

For example, AccessiBe states:

'accessWidget uses cutting-edge AI to remediate your website according to WCAG 2.1 Level AA standards, mitigating legal risk.'

AudioEye makes a similarly assertive statement:

'Fixing common accessibility issues can help you comply with the latest accessibility laws - reducing your risk of legal action.'

…whilst UserWay mentions:

'Supports ADA compliance and WCAG 2.1 & 2.2 conformance.'

But do these claims hold up?

^{*Statements correct at time of publishing}

How do overlays work?

Technically, overlays operate by:

• Querying and modifying the DOM
• Injecting role, aria-*, and tabindex attributes
• Overriding native event handling (e.g., for keyboard navigation)
• Guessing semantic relationships via pattern recognition

But here’s the issue: these changes occur after the page loads.

Assistive technologies like screen readers parse a page at render time. If the overlay applies changes after that point, they may go unnoticed or cause inconsistencies - sometimes even crashing the assistive software.

Real-world impact

Accessibility overlays are bandages that fail to address the deep structural and semantic issues that real users face. Worse still, they often degrade rather than enhance usability, conflict with assistive technology, and give organisations a false sense of legal and ethical security.

A case in point: I recently evaluated a website using AccessiBe. It included a Seizure Safe Profile - a feature intended to stop flashing or blinking animations that could trigger seizures in users with epilepsy. But it was off by default - meaning a user could be exposed to harmful content before they even discover a safety mode existed. Compounding the issue, the button used to activate AccessiBe had no descriptive label, leaving screen reader users in the dark. Unless the user already knew what it was and why they might need it, they would have no idea how to activate the very settings designed to protect them.

Despite the marketing claims, overlays simply cannot reliably correct fundamental accessibility failures.

Don’t just take my word for it

Real users, who depend on accessible websites, frequently share how overlays create more problems than they solve:

Here are just a few real-world experiences:

'I've had overlays disable my screen reader, reset my color preferences, and cover a good portion of my screen (unable to be minimised). All of those and others make it so difficult to interact with content that a lot of users will just not bother with those sites.' (reddit.com/r/accessibility)

'These overlays are so bad, disabled users have actively built systems to understand overlays as malware and have them blocked at a system and even a hardware router level.' (reddit.com/blind)

'I finally managed to gain access to my @NameCheap account by blocking #AccessiBe in my Windows Hosts file. I should not need to do this to use the Internet.' (Overlays Factsheet)

'I know with 100% certainty, any site which has deployed an overlay in the past year and a half has been less usable for both my wife and me - both blind.' (Overlays Factsheet)

What accessibility experts say

Accessibility professionals and advocates have been very outspoken in their warnings against overlays. In the article AudioEyes Will Get You Sued, Adrian Roselli, a Digital Accessibility Consultant and UX Designer, warns:

'Using AudioEyes overlay can add demonstrable WCAG failures and in some cases have no impact for users.'

This is not just an isolated opinion. In fact, hundreds of accessibility professionals have signed an open letter rejecting overlays as ineffective and counterproductive.

Problems overlays can’t fix

Overlays attempt to retrofit accessibility - but they can’t solve structural or semantic problems. Here are just a few examples:

Missing form labels: overlays may guess intent using placeholder text or visual proximity, but they can’t insert meaningful, semantic <label> elements where none exist.

Non-descriptive link text: "Click here" and "read more" links lack context. Overlays can’t invent missing information or rewrite content for clarity.

Illogical focus order: only a human can determine whether the reading and navigation order makes sense. Overlays can’t interpret visual layout or content hierarchy reliably.

The real solution - choose people, not overlays

Automation has its place, but manual audits and human judgment are essential. Only through real-world testing with assistive technology - screen readers, magnifiers, voice control - can you identify nuanced that issues overlays miss entirely.

Involve disabled users in design and QA. Educate developers. Make accessibility a core part of your process- not a patch applied after the fact.

Accessibility overlays are marketed as a quick fix, but in reality, they:

• Mask problems instead of fixing them
• Introduce new usability issues
• Interfere with assistive technology
• Provide a false legal security
• Undermine user trust and degrade experiences

Instead of gambling on overlays, invest in real accessibility:

• Conduct expert audits
• Include disabled users in testing
• Train your team
• Build inclusivity from the start

Need help with your accessibility journey? Learn more about our Accessibility Services.

About Zoonou

Zoonou is a UK-based software testing company. We’re a B Corp and 100% employee owned. Combining technical delivery and advisory services, we collaborate with the private, public and third sectors to create better software, services and products.