The Truth About Web Accessibility Overlays

Website accessibility overlays.As a nonprofit organization, you may have thought about accessibility and being inclusive to all of your website users. You may also have considered—or are already maybe using—a web accessibility overlay. Find out the truth about web accessibility overlays.

Using an overlay is not how you should go about making your website compliant. Anyone who suggests otherwise does not understand accessibility.

What an Accessibility Overlay Is

In case you’re not sure what an accessibility overlay is, it is technology that allegedly improves the accessibility of a website.

All you need to do is add a line of javascript code to your website. The overlay then analyzes and modifies the site at the browser level, as opposed to modifying any of the site’s code.

The Promises Made by Overlay Developers

Companies who sell overlays claim that your website will be fully accessible and compliant within a day or two, after you first add the code. It will also perform checks and fixes on an ongoing basis to ensure continuing compliance.

If only it were that easy.

They make other boastful claims such as:

  • “100%” or “up to 50% compliance” to laws ADA, Section 508 and WCAG 2.1 AA guidelines;
  • having a higher success rate than accessibility services.

They charge more for higher compliance rates.

Issues With Accessibility Overlays

1. Overlays just don’t work.

To put it simply, overlays just don’t work. The proof is the websites of the overlay vendors and their customers, whose sites are filled with accessibility issues despite using an overlay!

2. Overlays cannot detect or fix most accessibility issues.


An overlay is an automated tool. There is a huge limitation to what it can potentially detect, which is about 25% to 30% of accessibility issues. Those are the more black and white issues.

The majority of issues (70% to 75%) can only be found—and fixed properly—through manual checking, done by a person.

Of the issues it can even detect—again, within that 25% to 30% range—many cannot be properly fixed.

They also don’t make the documents on your website accessible. Those need to be accessible too! That is often overlooked.


An overlay can detect if an image has Alt-text, or alternative text. But it cannot determine if that Alt-text is sufficient or appropriate for the particular image. Only a human can determine that.

For example, there could be an image with a filename for the Alt-text: group-of-volunteers.jpg. An overlay would see that it has Alt-text and pass it, even though it’s completely inappropriate Alt-text.

On the other hand, there are some images that should not have Alt-text. Overlays cannot make that determination either.

Hyperlink text

Overlays cannot fix unclear hyperlink text. Say you have a hyperlink on the words “click here.” An overlay cannot determine if that’s appropriate link text and, if not, what to change it to instead.


Overlays do not fix contrast errors. That means that anyone with low vision or color blindness who may be visiting your website may not be able to read the text.

If an overlay could address contrast issues, what would it change it to? It could lighten or darken the color in question. But that could very likely change the look of the site, the feeling you want visitors to get.

It could also be a color outside of your brand color palette, which could make your site look completely disjointed and disconnected from your other marketing materials.

How much time and effort will that cost you to fix? How much will that cost your organization by looking unprofessional?


Overlays cannot fix the order of headings on a page. Heading order is important because it creates a structure for the content of a page. This benefits sighted users with and without a visual disability. It also conveys this structure to users of assistive technology such as a screen reader.

HTML tags

Overlays also cannot tell if text content on the page has been styled with the right HTML tag—for example, text that’s been styled as a paragraph that should actually be a heading instead, or a heading that really should be body text.


Forms on a website are often coded incorrectly and therefore create accessibility barriers.

The overlays I’ve seen didn’t add in the code to fix this. If there is an overlay that does that, I am not aware of it. But even if the overlay can add in that code, what will it use for it?

This affects what users of a screen reader will hear for the form fields. They could potentially not understand what the form fields are for, or they might input information in the wrong field.

After submitting the form, they may get alerted to errors in some form fields that they don’t understand how to fix. Worse, they may not be able to which field they are in and the error message isn’t clear—a usability nightmare.

They will give up and go elsewhere.

3, Overlays provide a false sense of security.

Overlays provide a false sense of security. One of the reasons you may want to make your site compliant is to abide by a specific law.

In the terms of service for these overlays, you are usually waiving any right to potentially make a claim against them. So, again, they may tout “full compliance,” but their terms say otherwise.

Legal fees could range from $1,000 to $100,000 per claim. That could include legal fines, settlement fees, lawyer fees for both sides plus eventual remediation costs. A court could order your organization to fix the website within a certain timeframe, but someone else could come along and make a claim.

Will the vendors of these overlays pay these fees on your behalf if your organization gets sued?

4. Overlays destroy usability.

Overlays destroy usability. They are a nightmare for users of assistive technology. This is evident when attempting to get around a website with an overlay.

Web visitors may be required to use the overlay to get around the website instead of what they are used to using, which could be a keyboard or a screen reader instead of a mouse.

This is a horrible user experience! It changes how someone is used to getting around a site, and now they also have to jump through a hoop to do so.

You may remember when websites were optimized for certain browsers and you’d see a message saying, “This site is best viewed in Internet Explorer.”

So sites with overlays might as well have a message that says, “This site must be navigated by using our widget, not your mouse, your keyboard or your screen reader.”

People will not only go elsewhere. They will tell others about that bad experience and that your organization just doesn’t care about their needs.

The outcry from users with blindness who’ve used websites with overlays has been loud and clear. The National Federation of the Blind made a statement about this:

… the Board believes that accessiBe [ an overlay company ] currently engages in behavior that is harmful to the advancement of blind people in society.

5. Overlays are unnecessary.

Overlays are unnecessary. Some sighted users who visit a website with an overlay are impressed by the widgets they see where they can change colors, increase text size, change the font or some other options. (These are not the only signs of an overlay. Some sites may use a minimal widget, which is not necessarily an overlay.)

There is nothing to be impressed with. If a site is made accessible, most of that functionality is already built into the site. Some of that functionality is also provided by the user’s operating system or the web browser.

6. Overlays slow down the website.

Overlays negatively affect the speed of your website. This presents several issues.

  1. Visitors will get frustrated waiting for pages to load.
  2. Visitors may leave.
  3. Your website’s search engine rank will be affected because Google uses page load time as a ranking factor, which means you may lose any competitive edge you may have in search results pages.

7. Overlays can break a site.

Overlays, at least custom ones, can break a website when changes in the site’s code are made, when the site is updated or you decide to change your theme.

8. Overlays can be a security issue.

Using a web accessibility overlay can open up your website to a potential security issue because of the inserted javascript.

Does the overlay company securely maintain their servers? Will they report any found security issues? What if your website gets hacked? Who will clean it up, and at whose cost?

9. Overlays are a waste of money.

Accessibility overlays are a waste of money. Using an overlay means you are continually throwing money at symptoms instead of addressing the underlying issues.

If a pipe under your kitchen sink bursts and leaks water all over the floor, are you going to keep sopping up the water with towels and place a bucket under it to catch the water, or are you going to fix the pipe, especially before the water causes damage to the floor?

It’s smarter to invest in remediating (fixing) the site and potentially training your team in some accessibility practices.

Need help with accessibility?

If you need help remediating your documents or websites, contact us about an estimate.

If you would like to train your in-house designers or developers in accessibility practices, check out the accessibility courses Colleen offers.

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