Comparison
Percelia vs. accessibility overlays
In short
An overlay is a JavaScript widget that promises accessibility in one click. The European Commission and expert bodies have made clear that overlays do not establish legal conformance, and they have themselves been the target of lawsuits. Percelia is not an overlay: it delivers real findings, source-code fixes and a defensible conformance statement.
People looking for an alternative to overlay vendors like accessiBe, UserWay or EqualWeb usually want the same thing: legally sound accessibility instead of a widget that papers over the problems. Here the overlay approach stands directly against Percelia.
Overlay vs. Percelia at a glance
| Overlay widget | Percelia | |
|---|---|---|
| How it works | A JavaScript layer that overlays the page at runtime in the browser | Assessment of the delivered page plus source-code fixes for your team |
| Legal conformance | Does not establish it, per the European Commission | A defensible, documented conformance statement (VPAT / EN 301 549) with human sign-off |
| Human review | No, fully automatic | Yes, human-in-the-loop for the ambiguous cases |
| What you get | One embedded line of script | A findings report with element, screenshot, criterion, fix and confidence |
| Effect on assistive tech | Can interfere with screen readers and keyboard use | No runtime layer that creates conflicts |
| Durability | Only works while the script is active | Fixes land permanently in the source code |
| Legal risk | Has itself been a target of lawsuits | Evidence-based, defensible documentation |
| Cost model | Ongoing subscription per domain | A one-off audit plus optional monitoring |
What overlays promise and what they deliver
Overlays advertise „accessibility in one line of code“. They can offer some cosmetic adjustments, such as a contrast mode, larger text or a read-aloud function. The problem: these tools sit as a layer on top of the page instead of fixing the causes in the markup. And many people with disabilities already use their own mature assistive technology, which an overlay can clash with.
Why overlays do not establish legal conformance
The European Commission has stated that overlays do not establish conformance with the accessibility requirements. For the BFSG and the European Accessibility Act what matters is whether the page itself meets the EN 301 549 criteria, not whether a widget sits on top of it. More in the guide on overlays vs. a real audit and the glossary.
What Percelia does instead
Percelia assesses the page as actually delivered across six analysis layers, maps every finding to a WCAG and EN 301 549 criterion and delivers concrete source-code fixes. A human reviews the ambiguous cases and signs off. The result is a documented, defensible conformance statement, not a runtime trick.
Frequently asked questions
- Are accessibility overlays illegal?
- Not in themselves. But they do not establish legal conformance: the European Commission has said so explicitly, and overlays have repeatedly been the target of lawsuits. They are not enough as BFSG evidence.
- Is Percelia an alternative to accessiBe or UserWay?
- Yes, but with a different approach: not a widget, but a real audit with source-code fixes and a defensible conformance statement.
- Does an overlay replace an accessibility audit?
- No. An overlay changes the page superficially at runtime; an audit uncovers the actual barriers and delivers permanent fixes in the source code.
- Is Percelia itself an overlay?
- No. Percelia installs nothing on your site and changes nothing at runtime. We assess the page from the outside and deliver findings plus fixes for your own team.
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