EPUB Accessibility Checker - EAA & Ace by DAISY Report

Runs Ace by DAISY and EPUBCheck on each EPUB and gives you a pass, review or fail summary for the European Accessibility Act (EAA), with the violations and the missing accessibility metadata. Made for publishers, distributors and self-publishing platforms that need to audit a backlist of ebooks.

Ace by DAISY is the standard open-source accessibility checker for EPUB (WCAG 2.x and EPUB Accessibility 1.1 rules, powered by axe-core). EPUBCheck is the W3C reference validator.

Input examples

Check a list of books:

{ "epubUrls": ["https://example.com/books/title-one.epub", "https://example.com/books/title-two.epub"], "maxBooks": 50 }

Check EPUB files stored in a key-value store, EPUBCheck only (fast validity check):

{ "epubUrls": [], "keyValueStoreId": "YOUR_STORE_ID", "runAce": false }

Get Ace messages in French:

{ "epubUrls": ["https://example.com/books/livre.epub"], "lang": "fr" }

The default input checks one public sample book.

Input guide

Field	What it does
epubUrls	Direct links to .epub files.
keyValueStoreId, recordKeys	Check .epub records stored in a key-value store.
runEpubCheck, runAce	Switch either checker off. Ace is the slower one.
saveFullReports	Save the complete Ace report.json and EPUBCheck JSON and link them in the row.
maxBooks, maxEpubMb, bookTimeoutSecs, lang	Limits and report language.

How the EAA verdict is decided

Verdict	When
fail	EPUBCheck reports fatal or error messages, or Ace finds critical or serious violations or WCAG A/AA violations of moderate or higher impact
review	No such issue, but EPUBCheck warnings, minor Ace violations, a checker that did not run, or missing required accessibility metadata (accessMode, accessModeSufficient, accessibilityFeature, accessibilityHazard, accessibilitySummary, conformsTo)
pass	No automated issue found. Manual review is still needed for full conformance

Output

One row per book.

Field	Meaning
title, creators, language, publisher	Book details from EPUBCheck
eaaVerdict, verdictReasons	pass, review or fail with the reasons
epubcheckErrors, epubcheckWarnings, epubcheckMessages	Validity results
aceViolations, criticalOrSerious, aceViolationsByImpact, topIssues	Accessibility violations grouped by rule with counts, files and help links
metadataGaps, conformsTo, accessibilityFeatures	Accessibility metadata status
aceReportUrl, epubcheckReportUrl	Links to the full JSON reports

Use it with

• A publisher's title list or catalogue export -> a list of EPUB URLs -> this Actor: a backlist audit with a sortable verdict per title.
• A scheduled run on newly delivered files from a distributor.
• Your remediation vendor: hand over the fail rows and topIssues.

FAQ

Is a pass the same as EAA compliance? No. Automated tools cover roughly a third of WCAG success criteria. A pass means no automated issue was found; reading order, meaningful alt text and similar items need a human review.

Does it need the book to be public? It needs a URL the Actor can download, or a key-value store record.

Honest limits

• Ace needs a few minutes for large illustrated books; the default limit is 300 seconds per book.
• Only the checks that EPUBCheck and Ace implement are reported. DRM-protected or encrypted EPUBs cannot be checked.
• The EAA verdict is a triage summary, not a legal opinion.

Price

Pay per event: $0.01 per book checked (book-checked). 100 books cost $1.00. Books that cannot be downloaded or that both checkers fail on are not charged.