Minutes to install, and the markup underneath is unchanged

What it is

An accessibility overlay is a script added to an existing site. It presents visitors with a toolbar of display preferences such as larger text, higher contrast or a readable font, and attempts automatic repairs to the page. accessiBe and UserWay are the best known.

What it is good at

• Speed of installation. One script tag, and something visible has changed the same day.
• Offering display preferences some visitors genuinely find useful, such as text sizing and contrast adjustment.
• Being inexpensive compared with remediation work.

What it leaves with you

• The markup, which is what assistive technology actually reads. A toolbar over the page does not change the underlying structure a screen reader interprets.
• The obligation. The Department of Justice states in its web guidance that it does not certify or approve any product or service as compliant, so nothing can confer compliance by being installed.
• Evidence. An overlay does not produce a record of what was tested and found.
• Anything the overlay publishes in your name. Some add a public conformance statement to the page, which becomes a claim you have made.

Side by side

Which to choose

Choose Accessibility overlays when

• Honestly: we do not think there is a case where an overlay is the right primary answer to an accessibility obligation, and we do not use one on any site. If you want the display-preference toolbar as a convenience for visitors, on top of a site that is actually accessible, that is a different and defensible decision.

Choose WebSpark when

• You want the barriers removed rather than covered.
• You need a dated record of what was tested, which is what a demand letter asks you to produce.

What switching costs

Removing an overlay is usually one script tag. The real work is whatever the overlay was covering, which is the remediation that was always the obligation. If a vendor has published a conformance claim on your behalf, take advice before removing it, because the claim and its removal are both things a claimant may look at.