GUIDE
What the UID Field Does in vCard
UID identifies a vCard instance for synchronization and change tracking. It is not automatically proof that two cards represent the same person.
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What you should know
UID identifies a vCard instance for synchronization and change tracking. It is not automatically proof that two cards represent the same person.
Before you begin
- Keep an untouched copy of the source export.
- Work on a small sample before changing a complete address book.
- Review the downloaded file before importing it elsewhere.
UID is an identifier, not a display field
A UID can remain stable while names or phone numbers change. It should not be shown as a person's name or merged into a phone number column.
Duplicate detection uses more than UID
Exports from different systems may generate different UIDs for the same person, while shared or copied UIDs can appear on unrelated cards. Combine UID evidence with phones, emails, and human review.
- Inspect UID values in a source copy.
- Compare duplicates using multiple signals.
- Preserve a chosen UID when merging cards.
- Validate the output and record the merge decision.
synchronization implications
Changing or removing UIDs can make a downstream CardDAV or address-book sync treat a card as new. Only rewrite them when the destination workflow explicitly requires it.
Questions people ask
Does What the UID Field Does in vCard change the original file?
No. The browser works with the selected copy and creates a separate download. Keep the original export as your rollback point.
What should I verify after What the UID Field Does in vCard?
Compare counts and representative fields, validate the generated copy, and test a small import before processing a full address book.