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Automated Accessibility Tools vs. Accessibility Overlays: A Comparison with Pros and Cons

March 4, 2024
Author: AO Editor


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Both automated accessibility testing tools and accessibility overlays, sometimes referred to as accessibility widgets, assist in making the web more accessible but have their limitations.

This article provides a high-level overview of what these tools are, how they are used, with a pros & cons comparison of each.

Automated accessibility testing tools automatically scan and identify potential accessibility issues that could hinder the ability of people with disabilities to interact with content online.

How To Use An Automated Accessibility Tool

Automated tools are best used as part of a broader accessibility strategy, helping to identify clear-cut issues that can be systematically addressed. 

However, they should be complemented by manual testing and expert evaluation to cover the full spectrum of potential accessibility barriers.

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What Is An Accessibility Overlay?

Accessibility overlays or widgets are third-party tools that can be added to a website with reported benefits of dynamic accessibility compliance remediation. They typically work by providing a floating interface that allows users to adjust the website's design and navigation features to better suit their needs, such as changing font sizes, color contrasts, or enabling screen reader support.

How Are Accessibility Overlays Used?

Accessibility overlays/widgets can offer quick, user-facing improvements and can be particularly useful for individuals with specific needs like color contrast, reductions in flashing content or “website busyness” and magnification.

Accessibility Overlays and Accessibility Widgets make accessing native accessibility features in Windows and Apple operating systems easier and convenient for users who do not need or rely on special assistive technologies.

People with significant disabilities are trained to use special software called assistive technologies to access digital environments. Such technology includes screen readers, voice navigation, facial recognition, eye-gaze technology, and switch controls for disabilities ranging from blindness to complete paralysis.

Pros & Cons Of Automated Accessibility Testing Tools


  •        Efficiency — They can quickly scan large amounts of content, making them a time-saving resource in identifying obvious accessibility issues.
  •        Consistency — Automated tests apply the same criteria uniformly across all tested content, ensuring consistent application of accessibility standards.
  •        Coverage — They can cover a wide range of technical accessibility issues that are clearly defined, like missing alt text for images or improper use of ARIA (Accessible Rich Internet Applications) attributes.


  •        Limited Insight — Automated tools can't catch all types of accessibility issues, especially those requiring human judgment, such as the relevance of alt text or the logical flow of content.
  •        False Positives/Negatives — They may sometimes incorrectly identify issues (false positives) or fail to detect real problems (false negatives).
  •        Lack of Context — These tools might not fully understand the context or purpose of certain web elements, leading to incomplete assessments.


Pros & Cons Of Accessibility Overlays

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  • Ease of Implementation. These tools can be quickly and easily installed on a website, often by adding a small snippet of code, making them appealing for website owners looking for quick fixes.
  • User Control. They offer users the ability to adjust websites according to their specific accessibility needs or preferences.
  • Immediate Improvement. For some users, these tools can provide immediate enhancements to their browsing experience on websites that may not have been fully accessible otherwise.


  •        Surface-Level Solutions. Overlays might address only the most visible issues, potentially leaving deeper, structural accessibility problems unresolved.
  •        Legal and Compliance Risks. Legal experts argue that relying on overlays alone is not sufficient to meet legal accessibility requirements, as they do not fix underlying code issues.

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Comprehensive Review Of 3 Accessibility Overlays

An in-depth article on accessibility overlays can be found here, which provides an objective analysis of 3 of the most widely used accessibility overlays, widgets, and a background on the emerging technology.

Share Your Thoughts On Accessibility Automated Testing Tools vs. Accessibility Overlays

Does your company or design agency use automated testing tools for digital accessibility compliance?

Have you outsourced accessibility compliance to an accessibility overlay or an accessibility partner?

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