Tiny Online Tools
Several exports, one address book
Contacts accumulate in copies: a phone export, a Gmail export, an old Outlook file. Each has a little the others do not — one has the photo, one has the mobile number, one has the job title. Merging them by hand is tedious; merging them automatically is dangerous. This does the tedious part and leaves the decisions to you.
Duplicate detection is a heuristic, and it says so
Two cards are scored against each other on five signals: an identical UID (1.00), a shared email address (0.95), a shared phone number compared on its last nine digits so a country prefix does not break the match (0.85), an identical normalised name (0.70), and a name plus organization match (0.80). That is a guess with a number attached, not a fact. A sensitivity slider sets the threshold, every group shows the score and the exact reasons behind it, and nothing is merged until you say so.
You will see the heuristic be wrong. Two people who share a household landline score 0.85. Two cards for the same person with no field in common score nothing at all. Both outcomes are visible, which is the point.
What each choice does
Keep the first takes the card from the first file. Keep the most complete takes the one with the most filled-in fields, weighting emails, phones, addresses and a photo. Merge fields unions the emails, phones, addresses, URLs and categories — dropping exact duplicates, comparing phones on their digits — and takes the longest non-empty value for each single-valued field. Keep both leaves the group alone. A card in no group passes through untouched.
Merging works on the original property lines rather than on an interpreted copy, so an embedded photo, a quoted-printable vCard 2.1 value and any X- property this parser has no opinion about all survive intact. The preview you see is produced by writing the merged card and reading it back, so it is exactly what the export contains.
Versions
The output can keep each card's own version or force 3.0 or 4.0. Forcing rewrites the VERSION line and nothing else — it does not translate properties between versions, and this is stated next to the control rather than buried here.
Privacy
Every file is read in your browser. Nothing is uploaded.