EPUB 3.3 STRUCTURE & PACKAGING

EPUB Health Check

Inspect one EPUB for container, package, navigation, link, and media problems before distribution. The tool reports problems without rewriting book content.

Validation basis

Normative checks are based on the finalized W3C EPUB 3.3 Recommendation. EPUB 3.4 is still a Candidate Recommendation, so draft-only requirements are not imposed.

This is a focused structural health check, not a replacement for the full EPUBCheck conformance test suite used by publishing workflows.

The EPUB is processed temporarily in memory. Book content and filenames are not added to analytics.