We never send any of your contact data anywhere, and never will. Your contact records - names, numbers, emails, photos - stay on your device, full stop. To improve the app we send a little first-party, anonymous usage data to our own servers: a random per-install ID that isn't linked to your identity, app and iOS version, device model, app language, and aggregate action counts (merges, kept-separates, cleanup edits, contacts and duplicate groups). Never your contacts, and never for advertising or cross-app tracking. Bug reports are no exception: if you attach contact data to help us reproduce an issue, it is anonymized automatically before it leaves your device - real names, numbers, and emails never reach us.
Will merges sync to iCloud / Google / Exchange?
Yes - same as any other contact edit on your phone. ContactOne writes through the iOS Contacts framework, so iCloud, Google, and Exchange propagate the merge to your other devices through their normal sync.
What happens if I undo a merge?
The original separate records come back exactly as they were - across all the accounts they belonged to. ContactOne keeps a full record of each merge until you explicitly clear it.
What if ContactOne suggests two people who aren't the same?
Tap Keep separate. Both contacts stay exactly as they are, and ContactOne remembers the decision - that pair never comes back as a suggestion. It's logged in History too, so you can reverse it if you change your mind.
Which account does a merged contact end up in?
You choose. Before merging, ContactOne shows a destination account picker listing every connected account with its contact count, so the merged record lands where you want it - not wherever the app guessed.
Can I back up my contacts before I start?
Yes, and we recommend it. One tap saves a full vCard snapshot of every contact to Files, iCloud Drive, or AirDrop, which you can re-import at any time. ContactOne also offers the backup inline right before your first merge.
Why is there a subscription if the app is on-device?
Because real human beings maintain and support this app and we need to keep doing that. The free tier is a real free tier - full scans, ten merges and a hundred cleanups - meant to let you see the problem before paying. After that, $24.99/yr or $4.99/mo keeps the lights on without ads or selling anything - or pay $39.99 once for a lifetime licence if you’d rather not have a subscription at all.
Can I see and move contacts between accounts?
Yes. The Accounts tab shows each of iCloud, Google, and Exchange on its own - separately, no auto‑merging - so you can see what's actually where. From there you can move any contact (or a selection) to a different account: useful when consolidating, switching jobs, or auditing a sync that's drifted. Moves are on‑device and undo‑able from History, same as merges.
Does it work on iPad and Mac?
iPhone and iPad today - both Dynamic Type and iPad-scale layouts are fully supported. A native Mac build (Designed for iPad) runs on Apple Silicon. No dedicated macOS app is planned - the iPad app on Mac is the path forward.
What languages does it support?
English, French, German, Hindi, Italian, and Spanish - all UI strings localized and name-matching tuned per locale (e.g. German umlaut folding). Want your language supported? Email help@contactone.app and let us know - we add languages based on the requests we hear.
Will it merge two people who just share a phone number?
No - that's exactly the mistake ContactOne is built to avoid. Matching looks at the whole record, not a single shared field, so two coworkers on the same office line (or a couple sharing a landline) stay separate. When it isn't sure, it asks you rather than guessing - and if you mark two people as “keep separate,” it remembers and won't suggest them again.
How do I know a merge won't quietly lose data?
Two ways. First, every original record is preserved and any merge undoes in a single tap, so nothing is ever truly gone. Second, because it's your data on the line, every release ships only after passing 450+ automated tests covering matching, merging, account handling, and undo - so the app you trust with your contacts stays rock-solid.
