EPUB Validator

A fast, free EPUB validator that analyzes files for structural integrity, metadata correctness, and standard conformance for publishers and developers.

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4.9 / 5.0

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About This Tool

The EPUB Validator analyzes EPUB packages to determine structural integrity, metadata correctness, and conformance to EPUB 3.x standards. It takes a ZIP-based EPUB, unpacks it, and checks essential components such as mimetype, container.xml, OPF file, and the spine and manifest relationships.
Conceptually, the tool performs file parsing, XML validation, and rule-based checks. It validates required elements, ensures unique IDs, verifies language tags and metadata formats, and flags issues that may hinder distribution or accessibility.
Who benefits: publishers, authors, QA engineers, librarians, and digital editors using established workflows. Unique value includes a comprehensive, machine-readable report, precise error localization, and support for export in JSON and CSV for automated pipelines.
Core features and use cases: deep structural validation, metadata verification, conformance checks for EPUB 3.x, accessibility considerations, and batch validation via API in enterprise setups. Typical use cases include pre-submission checks to retailers, quality assurance in publishing pipelines, and archival compliance.

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How to Use

Upload the EPUB file to the validator.
Select validation scope: structure, metadata, conformance, and accessibility if available.
Run validation to generate a report with errors, warnings, and recommendations.
Review findings, fix issues in your EPUB package, and re-upload to re-validate.
Download or copy the report for QA, compliance, and archival records.

Frequently Asked Questions

Find Quick Answers

What does EPUB validation include?

It checks the EPUB packaging, presence of mimetype, container.xml, OPF metadata, spine order, manifest items, and conformance to EPUB 3.x guidelines; it also flags structural and encoding issues critical for distribution.

Can I validate multiple files at once?

Batch validation is available via API or enterprise plan; you can queue multiple EPUBs and obtain individual reports per file, enabling automated QA in publishing pipelines.

What outputs are produced?

The tool returns a machine-readable JSON report and a human-readable summary; optionally CSV export for integration with CI systems.

Are DRM-protected EPUBs supported?

DRM-protected or encrypted EPUBs cannot be validated; the tool operates on accessible ZIP packages and reports unsupported content.

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