Package health
Checks container.xml, the OPF package, manifest files, and declared EPUB version.
Private browser utility
Check an EPUB Before You Read, Send, or Repair It.
Inspect metadata, cover declarations, package files, navigation, reading order, CSS, and common spacing problems. The EPUB stays on your device.
Select a DRM-free EPUB to run a local preflight. You will get a readable report, not a vague pass/fail badge, and the original file is never modified.
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Choose an EPUB to inspect
Your book is opened only in this browser tab. It is not uploaded, stored, or sent to EpubTidy.
DRM-free EPUB • Up to 250 MB • Nothing leaves your device
This is a practical browser-based preflight, not the official EPUBCheck conformance suite. A passed check does not guarantee acceptance by every store or reading system. For repair guidance, visit the EPUB Editor & Repair page.
What the checker looks for
Useful signals before a full repair
EPUB files are ZIP packages containing XML, HTML, CSS, images, navigation, and metadata. A book can open in one reader while still carrying problems that appear elsewhere.
Metadata & cover
Finds missing title, language, identifier, creator, or an absent and broken cover declaration.
Reading order
Reviews spine references and EPUB 3 navigation or EPUB 2 NCX availability.
Formatting clues
Flags common locked-font, rigid-width, zero-width character, and repeated spacing patterns.
Questions before you check
EPUB Checker FAQ
Is my EPUB uploaded to a server?â–¼
No. The checker reads the selected file inside your current browser tab. The EPUB and its metadata are not uploaded to EpubTidy or stored by this website.
What does the EPUB checker inspect?â–¼
It reviews the EPUB package, required metadata, embedded cover declaration, manifest resources, spine, navigation, protected-resource declarations, and several common CSS and spacing patterns.
Is this the official EPUBCheck validator?â–¼
No. This is a fast browser-based preflight for common library and reading problems. Use the official EPUBCheck project when formal specification conformance is required.
Can this tool repair my EPUB?â–¼
The web checker is read-only. EpubTidy for iPhone and iPad can edit metadata, replace covers, clean common formatting problems, and export a corrected DRM-free EPUB.