Overlay tools and automated checkers are often adopted as quick fixes. While they can aid some users, they cannot replace a fundamental, code-level commitment to accessibility.
Creating truly accessible digital services means ensuring that everyone, including disabled users, can perceive, navigate, and interact with your website from code to content. Relying on overlays and automated testing will not be sufficient to achieve this.
What is an accessibility overlay?
A plug-in or script layered atop your site, overlays (e.g., toolbars offering contrast and font adjustments, text-to-speech options) can assist users with mild visual or cognitive needs.
However:
- They do not fix underlying code issues: missing alt-tags, non-semantic markup, broken keyboard navigation, etc.
- Users relying on screen readers or speech recognition software can’t utilise overlays if the site’s code blocks access to controls in the first place.
Overlay failures: legal & user implications
In January 2025, the U.S. FTC ordered AccessiBe to pay $1 million after a determination that their overlay (“accessWidget”) falsely claimed to make websites fully WCAG-compliant. The order explicitly bans misleading compliance claims and requires clear disclosure of any connection to third-party reviewers.
This case highlights key risks:
- Overlays can’t guarantee compliance
- Many disabled users still hit accessibility barriers
- Regulatory scrutiny is increasing
Automated testing tools: Useful, but limited
Automated checkers can detect obvious issues: missing alt text, poor contrast, heading errors, etc. They provide low-hanging fruit remediation but are insufficient alone.
Coverage studies show:
- Only 30–40% of WCAG issues are detected via automation.
- In some analyses, automated tools detect just 20–30% of accessibility failures.
- Even broader scans (13,000+ page audit completed by Deque) report ~57% detection.
Key limitations:
- They don’t catch issues affecting usability via screen readers, logical focus navigation, meaningful labels, or dynamic content.
- They cannot replicate real-world use by people with disabilities.
- Manual and user testing are required to meet legal and practical WCAG standards.
Conclusion
In summary, while accessibility overlays and automated tools can provide useful enhancements and help catch some of the more obvious issues, they should never be mistaken for a complete solution. Overlays simply add an extra layer of support for some users but cannot replace properly coded, in-built accessibility. Similarly, automated checkers are only semi-effective, typically identifying around 30–50% of potential issues, and often missing more complex barriers that real users encounter. The recent fine against AccessiBe is a clear reminder of the risks involved in relying on these tools alone and making sweeping compliance claims.
To genuinely create accessible digital experiences and meet legal obligations, overlays and automated tools should be seen as helpful components within a much broader, ongoing commitment to accessibility – not as a substitute for doing the work properly in the first place.