Knowho – Your Personal Whitelist of Trust for iPhone
Knowho
Your personal whitelist of trust. Unlike spam blockers — only the numbers you choose to trust get a name.
The Problem
Spam-blocking apps work from a blacklist: they only catch known bad numbers. Voice phishing scammers simply rotate through fresh numbers — and slip right through.
Knowho flips the model. Instead of blocking the bad, you whitelist the good. Any number not on your list? Stay alert. It doesn’t matter how new or “clean” the number is.
What Knowho Does
Paste text from any app — a messenger chat, an SMS, a note — and Knowho automatically extracts the phone numbers and names, then registers them with iOS’s call system. The next time one of those numbers calls you, your iPhone shows who it is.
No servers. No cloud sync. Everything stays on your device.
Key Features
| Feature | Detail |
|---|---|
| Whitelist-based caller ID | Only numbers you register get identified |
| Smart text extraction | Paste any text; numbers and names are pulled out automatically |
| Completely offline | No server, no account, no internet required |
| Separate from iOS Contacts | Numbers stay in Knowho — never synced to iCloud Contacts, iMessage, or KakaoTalk |
| Multi-language support | English, Japanese, Korean — international number formats detected automatically |
| Share Extension | Import directly from any app with a share button |
How It Works
Step 1 — Paste or share text Copy a message from any chat or note, paste it into Knowho — or use the share sheet directly from any app.
Step 2 — Review extracted contacts Knowho highlights the phone numbers and suggested names it found. Edit anything before saving.
Step 3 — Call comes in, you know who iOS shows the registered name on your lock screen — powered by Apple’s CallKit, with zero data leaving your phone.
Screenshots
Pricing
| Free | Pro | |
|---|---|---|
| Contacts | 20 | 5,000 |
| CSV import | — | ✓ |
| iCloud backup & restore | — | ✓ |
| Offline & private | ✓ | ✓ |
| Share Extension | ✓ | ✓ |
Pro is a one-time in-app purchase.
Why Not Just Use the Contacts App?
iOS Contacts syncs everywhere — iCloud, iMessage, and third-party apps like Messenger App all pick up your contacts automatically. Sometimes that’s exactly what you don’t want: delivery drivers, temp work numbers, client contacts that shouldn’t show up as chat friends.
Knowho is a private, siloed list. It identifies callers without polluting your real address book.