Prove it's really them.
Countersign.me lets you verify, mid-call or mid-chat, that you're really talking to your contact — not a deepfake or a cloned voice. One tap, one spoken code, a few seconds.
No accounts · Works alongside any call or chat app
Seeing and hearing used to be enough. Not anymore.
Voice-cloning and deepfake video have made "it sounded just like them" an unreliable signal. A panicked call from a family member. A video meeting with your boss asking for a wire. A friend messaging that they're locked out and need help — right now. When you can't trust your eyes and ears, you need something an impersonator can't fake.
Pair once. Verify in seconds, forever.
Countersign.me is a companion to whatever you already use — it hosts no calls or chats of its own.
Pair once
Scan each other's QR code in person, or send a one-time invite link. It takes a few seconds, and you only do it once per person.
Tap Verify Now
Mid-conversation on any app — phone, video, or chat — open Countersign.me and start a check. Your contact approves with their face or fingerprint.
Compare the code
Both phones show the same two words and four digits. Say them aloud or compare on screen. A match means it's really their paired device, with a live person behind it, right now.
We tell you exactly what a match means — and what it doesn't.
Countersign.me makes a precise, cryptographic promise instead of a vague one. That honesty is the whole point.
The person is on the exact device you paired with them, and just passed a live face or fingerprint check on it seconds ago — something a recording or a deepfake can't reproduce.
It isn't identity-checking a stranger or reading minds. It confirms it's the same trusted person's device with a live human present — not who someone legally is.
Countersign.me runs alongside your call or chat. It has no access to your audio, video, or messages — nothing about your conversation ever reaches us.
The guarantee is math backed by your phone's secure hardware — not an AI trying to spot a fake in an arms race it can't win.
Built to know as little about you as possible.
No accounts, ever
No sign-up, no email, no phone number. Your device itself is your identity.
Keys in secure hardware
Your identity key lives in the Secure Enclave or Android Keystore — it can't be exported, phished, or restored by an attacker.
No tracking, no ads
No analytics SDKs, no advertising, no data brokers. Nothing to sell, because we collect nothing to sell.
A server that knows nothing
Our "blind relay" carries only sealed, unreadable messages that vanish within minutes. It never sees your contacts or content.
Free to start. One-time to go unlimited.
No subscription. Your unlock survives a reinstall without any account. And answering a verification is always free — for everyone.
- Up to 3 paired contacts
- Full verification, no limits
- Hardware-backed security
- Unlimited paired contacts
- No subscription, ever
- Restores free on any device
Invitees never pay. Responding to a verification and accepting a pairing invite are always free, no matter how many contacts you have — so anyone can confirm it's really you.
No consumer tool can promise perfection — so we won't.
Countersign.me raises the bar dramatically against impersonation. Here's where we're careful about what we claim.
Real-time relay attempts
An attacker who has you on the line could try to relay a verification to your real contact at the same instant. We fight it with spoken codes, an explicit "are you on a call right now?" prompt, and an immediate alarm if the real contact says they're not — but no consumer system eliminates it entirely.
Remote pairing is trust-on-first-use
Pairing in person by QR is the gold standard. Pairing over an invite link trusts that the link reached the right person, so those contacts carry a visible "unconfirmed" badge until you upgrade them in person.
Questions, answered plainly.
Does it record or listen to my calls?
No. Countersign.me never has access to your calls, video, or messages. It runs alongside whatever app you're already using and only handles the verification itself.
What happens if the codes don't match?
You get an immediate alarm telling you to hang up and reach the person another way. A mismatch is exactly the warning you want — it means the device or the person on the other end isn't who they claim to be.
Do both people need the app?
Yes — verification is mutual, so both sides run Countersign.me. Sending someone an invite and helping them set up is quick, and responding to verifications is always free. An invitee never has to pay.
What if I get a new phone?
Your identity key is tied to your phone's secure hardware, so a new phone means re-pairing with your contacts. That's deliberate: a changed key is treated as untrusted until you re-pair, the same way Signal handles safety-number changes.
What do your servers actually store about me?
Almost nothing. No accounts, no contact list, no message content — only a sealed, unreadable message queue that clears within minutes. See our Privacy Policy for the full detail.
Be sure it's really them.
Countersign.me is coming to iOS and Android. Leave your email and we'll tell you the day it's live — no spam, just the launch.