What are accessibility overlays and why don't they work?

Accessibility overlays are JavaScript widgets embedded via a code snippet that promise to make a website accessible automatically and retroactively, often combined with a control panel for font size or contrast. The idea of compliance at the push of a button is tempting, but does not hold up in practice.

Accessibility specialists and disability associations explicitly warn against these tools (Source: W3C WAI, Overlay Fact Sheet). They do not fix the structural causes in the source code, frequently collide with users' own assistive technologies, and can thereby make operation even worse. Lawsuits already exist against websites that remained unusable despite an overlay.

The BFSG demands real, structural accessibility in the source code. Instead of masking symptoms, we fix the causes, sustainably and verifiably. How we proceed, you can read under services.