EPUB Inspector
Read EPUB metadata, TOC, file list and cover image without unpacking the body.
Overview
The EPUB inspector opens an .epub file and surfaces the structural information a reader app uses to render it — the package metadata, the table of contents, the manifest of every internal file, and the cover image — without unpacking or rendering the body content itself.
Self-published authors verifying that an exported EPUB is valid, librarians cataloguing donated digital collections, and developers debugging an e-reader pipeline reach for this when a deeper look than a metadata viewer is required. Long-tail searches that lead here include "view EPUB internal structure", "list files inside EPUB", and "inspect EPUB cover and TOC".
How it works
An EPUB is a ZIP archive conforming to the IDPF / W3C EPUB specification. Inside, META-INF/container.xml points to the root package file (typically content.opf), which in turn lists every spine item, metadata field, and resource in the manifest. The inspector parses these XML documents to build a tree view of the book's logical structure.
The table of contents is read from either the EPUB 3 navigation document (nav.xhtml) or, for EPUB 2, the NCX file. The cover image is located by walking <meta name="cover"> references or properties="cover-image" flags. Internal files are listed with size, MIME type, and compression status — all the markers that matter when validating a build.
Examples
- Confirm your EPUB has both an NCX and a nav document (some retailers still require both).
- Spot oversized images bloating the package — anything above a few hundred kilobytes per illustration is worth investigating.
- Verify the spine order matches the intended reading sequence.
- Preview the embedded cover image before submitting to a storefront.
FAQ
Does it validate against the EPUB spec?
The inspector parses and reports — it does not run the IDPF validator. Use a dedicated validator for retailer submission.
Will it show DRM-protected content?
DRM-wrapped EPUBs typically encrypt the body resources. Metadata and manifest may still be visible, but text and images will not be readable.
What is the difference between EPUB 2 and EPUB 3?
EPUB 3 uses HTML5 and a nav.xhtml document; EPUB 2 uses XHTML 1.1 and an NCX. The inspector handles both, and many EPUB 3 files still ship an NCX for legacy reader compatibility.
Can I see the chapter text?
Not directly — the inspector deliberately surfaces structure, not body content. Use an EPUB reader for the actual prose.
Why is my "EPUB" not parsing?
Check that the file is a real ZIP. Some sources hand out renamed PDF or AZW files; the inspector relies on the ZIP signature to begin parsing.