Built for the way your contacts actually look — messy.

One name across iCloud, Google, and Exchange. Two photos that disagree. A phone number that's been wrong since 2014. ContactOne treats each as a question, not a guess.

/01 — Detect

Finds the duplicates iOS pretends aren't there.

iOS visually merges contacts linked across accounts, but the underlying records stay split. ContactOne reads them honestly — fuzzy-matching names, emails, phones, and birthdays — and groups what belongs together.

ContactOne duplicates list
/02 — Decide

You pick, field by field.

Every conflict is shown side-by-side with the source labeled. Pick the right photo, the right job title, the right number. Nothing is silently overwritten.

SC
aria@icloud.com
Adopted · iCloud
SC
aria.huang@gmail
Kept · Google
↓ merge into one
/03 — Private

Stays on your phone. Always.

Matching, merging, undoing — all of it runs on your device using the system Contacts framework. There is no ContactOne server. There is no account to sign up for.

/04 — Reversible

Every merge has an undo.

Changed your mind a week later? Open History, tap Undo. The original separate records come back, intact. You're never one tap away from a regret.

ContactOne merge history
/05 — Yours

Four palettes, both modes.

Pick the look that matches your home screen — clay, indigo, forest, or mono — and the app icon changes with it. A small thing. Most people change it once and forget. We like that.

Clay
Indigo
Forest
Mono
/ also — not the headline, but useful

See what's in each account. Move what doesn't belong.

The Accounts tab shows what's actually living in iCloud, Google, and Exchange — separately, no auto‑merging. From there you can move any contact (or a batch) to the account where it should be. Useful when you're switching jobs, consolidating into one place, or quietly auditing a sync that's been off for years.

Browse · one account at a time Move · undo‑able, like merges

Merging is just the start. ContactOne tidies the details, too.

Once the duplicates are gone, the little inconsistencies remain — a number with no country code, a SHOUTING email, a stray “Work 2” label. Run a cleanup pass and fix them in bulk, or write your own rule.

Remove broken links

Dead Facebook URLs, defunct Skype handles, links that 404. ContactOne flags the ones that no longer resolve so you can drop them.

Linkfacebook.com/deactivated
Removed— link cleared

Normalize phone numbers

Add the country code and a leading “+” so every number is in full E.164 format — and dials correctly when you're travelling.

Was4165551212
Now+1 (416) 555-1212

Lowercase emails

Optional, and off by default. Turn it on and mixed‑case addresses collapse to clean lowercase — you decide whether that's your style.

WasSarah.Chen@Work.COM
Nowsarah.chen@work.com

Tidy labels

Merge the accidental duplicates iOS creates — “Work 2”, “iPhone”, “_$!<Home>!$_” — back into clean, standard labels.

Was_$!<Work>!$_ · Work 2
NowWork

Fix name casing

All‑caps imports and lowercase typos become proper case — while preserving names that are meant to be unusual, like “McKenzie” or “van der Berg”.

WasDAVID reyes
NowDavid Reyes

Your own rules

Build a rule for the quirk that's yours alone — strip a legacy prefix, standardize a company name, retag an old account. It runs on every matching contact.

RuleCompany “FB” → “Meta”
Applied312 contacts updated

From 1,283 to 1,085.
198 fewer to scroll past.

Download on theApp Store Free · iPhone & iPad · iOS 16+