Introduction, definition, and history of web accessibility overlays
Overlays are a broad term for technologies aimed at improving the
accessibility of a website by applying third-party source code (typically
Website add-on products purporting to improve accessibility go back to the
late 1990s with products like Readspeaker
and Browsealoud. Both
of which added text-to-speech capabilities to the website(s) on which they
Later, similar products came to market that added additional tools to
their software that allow user-based control of things like font-sizes and
changes to the web pages colors so that contrast is improved. Products like
Userway, EqualWeb, AudioEye, User1st, MaxAccess, FACIL’iti, and accessiBe fall into this category.
These products are sometimes also white labelled under additional names.
Overlay widgets are unnecessary and are poorly placed in the
As stated above, some overlay products contain widgets which present a
series of controls that modify the presentation of the page they’re on.
Depending on the product, those changes may do things like change the page
contrast, enlarge the size of the page’s text, or perform other changes to
the page that are intended to improve the experience for users with
To laypersons, these features may seem beneficial, but their practical
value is largely overstated because the end users that these features claim
to serve will already have the necessary features on their computer, either
as a built-in feature or as an additional piece of software that the user
needs to access not only the Web but all software.
On this latter point, it is a mistake to believe that the features
provided by the overlay widget will be of much use by end users because if
those features were necessary to use the website, they’d be
needed for all websites that the user interacts with. Instead, the widget is
as—at best—redundant functionality with what the user already has.
Strengths and weaknesses of automated repair
While some automated repair is possible, customers should be
discouraged from using an overlay as a long-term solution.
Some overlay products have capabilities aimed at providing accessibility
repairs to the underlying page on which the overlay is added. These repairs
are applied when the page loads in the user’s browser.
While it is true that a non-trivial array of accessibility problems can be
repaired in this manner, the nature, extent, and accuracy of such repair are
limited by a number of important factors:
- Automated application of text alternatives for images is not
- Automated repair of field labels, error management, error handling, and
focus control on forms is not reliable
- Automated repair of keyboard access is not reliable
- Modern, component-based user interfaces, such as those using ReactJS,
Angular, or Vue may change the state of all or some of the underlying page
independently of the overlay, rendering it unable to fix those
- Repairs to the page can either slow down page load times or cause
unexpected page changes for assistive technology users.
In addition to the above, overlays do not repair content in Flash, Java,
Silverlight, PDF, HTML5 Canvas, SVG, or media files.
An additional class of product exists, which only perform automated
repairs and are marketed as a temporary solution. These include Amaze by
Deque Systems, Alchemy by Level Access, and Sentinel by Tenon.
For purposes of this document, these products aren’t considered to be in
the same class of product as the overlays that provide widgets. The most
notable difference, beyond the lack of a “widget” is that Amaze,
Alchemy, and Sentinel are understood by their manufacturers as being intended
for use as an interim solution.
Fitness for achieving compliance with accessibility standards
While the use of an overlay may improve
compliance with a handful of provisions in major accessibility standards,
full compliance cannot be achieved with an overlay.
Among the many claims made by overlay vendors is the claim that the use of
their product will being the site into compliance with accessibility
standards such as WCAG 2.x, related and derivative standards, and laws that
mandate compliance with those standards.
Conformance to a standard means that you meet or satisfy the
‘requirements’ of the standard. In WCAG 2.0 the
‘requirements’ are the Success Criteria. To conform to WCAG 2.0, you need
to satisfy the Success Criteria, that is, there is no content which
violates the Success Criteria.
WCAG 2.0: Understanding Conformance
Given that conformance is defined as meeting all
requirements of the standard, these products’ documented inability to repair
all possible issues means that they cannot bring a website into compliance.
Products marketed with such claims should be viewed with significant
No overlay product on the market can cause a website to become fully
compliant with any existing accessibility standard and therefore cannot
eliminate legal risk.
Accessibility on the Web is a big challenge, both for owners of websites
and for the users of those websites. The invention of novel approaches to
resolving this challenge is to be commended.
However, in the case of overlays—especially those which attempt to add
widgets that present assistive features—the challenge is not being met. Even
more problematic are the deceptive marketing provided by some overlay
vendors who promise that implementing their product will give their
customer’s sites immediate compliance with laws and standards.
The ineffectiveness of overlays is something that has broad agreement among
accessibility practitioners, per the WebAIM Survey of Web Accessibility Practitioners
A strong majority (67%) of respondents rate these tools as not at all or not very effective. Respondents with disabilities were even less favorable with 72% rating them not at all or not very effective, and only 2.4% rating them as very effective.
As a result of the above information:
- We will never advocate, recommend, or integrate an overlay which
deceptively markets itself as providing automated compliance with laws
- We will always advocate for the remediation of accessibility issues at
the source of the original error.
- We will refuse to stay silent when overlay vendors use deception to
market their products.
- More specifically, we hereby advocate for the removal of accessiBe,
AudioEye, UserWay, User1st, MK-Sense, MaxAccess, FACIL’iti, and all similar products and
encourage the site owners who’ve implemented these products to use more
robust, independent, and permanent strategies to making their sites