- What is a VCF file and how do I export one?
- A VCF (vCard) file is the standard format for exchanging contact information — names, phone numbers, emails, addresses, and more. On iPhone, go to iCloud.com → Contacts → select all contacts (Edit → Select All) → Export vCard to download a single .vcf with all contacts. On Android, open the Contacts app → Settings → Export → save as .vcf. Google Contacts lets you export from contacts.google.com → Export → vCard format. Outlook exports from File → Open & Export → Import/Export → Export to a file → choose vCard (.vcf).
- What is Levenshtein distance and why does it help find duplicates?
- Levenshtein distance counts the minimum number of single-character edits (insertions, deletions, or substitutions) needed to turn one string into another. A distance of 1 means one character is different — so "Jon Smith" and "John Smith" are 1 edit apart (an inserted 'h'). This catches typos, nickname variants, and minor spelling differences that exact matching misses entirely. You can adjust the sensitivity slider: 0 = exact names only, 1 = one-character difference (recommended), 2 = two characters, 3 = broader fuzzy matching.
- How does phone number matching work?
- All non-digit characters (dashes, spaces, parentheses, plus signs) are stripped from each phone number. If the result is 11 digits starting with 1 (North American format), the leading 1 is removed to produce a 10-digit core. Numbers with at least 7 digits are then matched by their last 10 digits, so "+1 (555) 123-4567", "555-123-4567", and "15551234567" all resolve to the same fingerprint and will be detected as the same phone number.
- Will the tool delete contacts automatically?
- No. Every potential duplicate group is shown to you for manual review. You choose which version to keep for each group, or you can skip a group entirely to leave both contacts untouched. Nothing is changed until you click "Download clean-contacts.vcf" — and even then your original file on disk is never modified. The downloaded file is a brand-new file.
- What does "Merge fields" do?
- When you tick "Merge all TEL/EMAIL fields into kept contact" in a duplicate group, the tool does not just keep one raw vCard — it builds a merged card that starts with the selected contact's full vCard and then appends any TEL and EMAIL lines that appear in the other cards of the group but not in the selected one. This prevents data loss when different duplicates hold different phone numbers. Note: only TEL and EMAIL fields are merged; other properties (ORG, ADR, NOTE, etc.) are taken from the kept card only to avoid garbled records.
- Can I re-import the downloaded VCF into my phone or Google Contacts?
- Yes. The downloaded file is a valid UTF-8 vCard file. On iPhone, AirDrop or email the file to yourself, then tap it in the Files or Mail app to import into Contacts. On Google, go to contacts.google.com → Import → choose the file. For Outlook, use File → Open & Export → Import/Export → Import a vCard file. It is best practice to first delete or hide your existing contacts before importing the cleaned file, or use your contacts app's built-in "Merge duplicates" feature after import to handle anything this tool missed.
- Is my data safe? Do you store or transmit my contacts?
- Your contacts are never uploaded to any server. The entire process — parsing, fuzzy matching, merging, and download — happens inside your browser using the JavaScript File API and Blob API. There is no backend server for this tool. When you close or refresh the page, all contact data is discarded from memory. You can verify this yourself by opening your browser's Network DevTools tab and observing that no requests are made while the tool is running.