Knowledge · Rule
Missing required metadata (title, language, identifier)
Metadata · E-OPF
Definition
Your package file (OPF) is missing required metadata KDP expects: title, language, or a unique identifier.
Why
- dc:title, dc:language, or dc:identifier omitted from package metadata.
- Empty title/identifier elements left by a broken export.
- Unique-identifier attribute on <package> does not match any dc:identifier id.
- Language code missing or not a recognizable tag (e.g. blank instead of en).
Impact
May block submission on KDP when this rule fails.
Platforms
| Platform | Result |
|---|---|
| KDP | May reject |
| Apple Books | May reject |
| Google Play | May reject |
| Kobo | May reject |
References
- EPUB Packages — metadata
- Amazon KDP metadata help
- Cermify Rule Set kdp-epub-2026-07
Last updated · 2026-08-03
Why we believe
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