Most EPUB distribution friction comes from metadata drift, not visible typography. Use this checklist to keep title, author, identifiers, language, and navigation metadata consistent before upload.
Lock metadata values before final export
Freeze title, subtitle, author display name, and series naming before your release-candidate export.
Use one canonical author format everywhere so retailer ingestion does not split author records.
If contributor roles are used, keep role naming consistent across revisions.
Verify required package metadata fields
Confirm language code, unique identifier, publication date, and publisher fields are present and valid for your distribution plan.
Ensure the identifier strategy (ISBN or platform-specific ID) is intentional for this edition.
Keep metadata text clean and plain; avoid hidden control characters from copied source notes.
Check navigation and metadata together
Metadata correctness and navigation correctness should be validated in the same QA pass.
A clean TOC with mismatched title/author metadata still causes storefront ingestion quality issues.
Run validator checks after any metadata change, not only after chapter edits.
Run distributor-ready release checks
Open the final EPUB in at least two reading environments and verify title/author display plus TOC behavior.
Confirm the exact file uploaded to distribution is the same file that passed metadata validation.
Archive one final validated EPUB per edition and keep its checksum in release notes.
Numbers and Reference Tables
EPUB Metadata QA Reference
Field
Pass signal
Common failure pattern
Title + subtitle
Matches storefront listing and cover text
Old working title still in package metadata.
Author/contributor
Canonical naming is consistent
Name variant causes duplicate author entries.
Language
Valid language code (for example, en)
Missing or malformed language value.
Identifier
Unique value mapped to edition strategy
Identifier missing or duplicated across editions.
Publisher/date
Release metadata is current and intentional
Placeholder metadata shipped to production.
Publish Checklist
Lock final title, subtitle, and author naming for the edition.
Confirm metadata values match planned storefront listing.
Set valid language code and verify it is not empty.
Set unique identifier strategy (ISBN or platform-specific) intentionally.
Confirm publisher and publication date fields are current.
Export a fresh EPUB from the final manuscript state.
Run EPUB validation and capture metadata-related findings.
Click TOC links to confirm navigation remains stable after metadata updates.
Test title/author rendering in at least two reading environments.
Upload only the validated release EPUB and archive that exact file.
Warning-to-Fix Map
Warning pattern: missing required metadata field
Fix: Populate missing package metadata values in source/export settings and regenerate EPUB.
Verify: Validator reports no missing-core-metadata errors.
Warning pattern: invalid language code
Fix: Replace malformed language string with a valid BCP-47 language tag.
Verify: Language metadata warning clears in validation output.
Warning pattern: duplicate or conflicting identifier
Fix: Set one clear identifier strategy per edition and remove stale identifier entries.
Verify: Validator and distributor precheck show one valid unique identifier.