How WhatsApp, Telegram and Signal Verify Your Number
Contents
WhatsApp, Telegram and Signal all register an account to a phone number and confirm it with a one-time code. They differ in where that code goes and in what protects the account afterwards. Telegram sends the code to your other logged-in devices before it uses SMS. WhatsApp and Signal text it or call with it. All three let you add a PIN or password that the next person to register your number would also need. On a messenger whoever registers the number gets the account, so the PIN or password is what stops someone who has the code.
How do the three compare?
| Telegram | Signal | ||
|---|---|---|---|
| Where the code goes first | SMS, with a voice call as an alternative | The Telegram app on your other logged-in devices | SMS, with a voice call as an alternative |
| Extra lock | Two-step verification PIN, 6 digits | Two-Step Verification cloud password | Registration Lock, using your Signal PIN |
| If you forget the lock | Reset by email if you added one, otherwise wait 7 days | Reset through a recovery email, or request a reset from a signed-in device and wait 7 days | The lock lapses after 7 days without using Signal |
| Who sees your number | Your contacts and people you message, unless you chat with them by username (rolling out since 2026) | Controlled in privacy settings | Only people who already have it saved; others can reach you by username |
| Account per number | One | One, with up to three accounts per app | One |
How does WhatsApp verify your number?
WhatsApp texts a six-digit code to the number, and offers a voice call if the text does not arrive. After a few failed attempts it makes you wait before it sends another code, and the wait grows with each request. The WhatsApp code not arriving guide covers those timers.
Registering the number on a new phone signs the old phone out. That is the reason for two-step verification, a six-digit PIN set under Settings, Account. With it on, anyone who registers your number needs the code and the PIN. If you forget the PIN, WhatsApp can send a reset link to the email you added when you set it up. Without that email, you wait seven days before you can register without it. Linked devices, such as WhatsApp on a computer, connect by QR code from the main phone and need no SMS code.
How does Telegram verify your number?
Telegram sends the login code as a message inside Telegram, to every device where you are already signed in. Only when there is no other session, or when you tap the option saying you did not get the code, does it fall back to SMS or a call. People who wait for a text while Telegram is open on their laptop are usually waiting for a message that already arrived in the app.
Two-Step Verification adds a cloud password that Telegram asks for after the code. Set a recovery email with it, because without one, a forgotten password can only be reset from a device that is still signed in, and the reset takes 7 days. Telegram also lets one app hold up to three accounts, and it deletes an account that stays offline for the period set under Settings, Privacy and Security. Telegram’s FAQ gives 18 months as the default.
Telegram is also the only one of the three that can register an account without a SIM at all. It accepts anonymous +888 numbers bought on the Fragment marketplace, paid for in the TON cryptocurrency.
How does Signal verify your number?
Signal sends a code by SMS or by voice call. After registration you set a Signal PIN, and Registration Lock, under Settings, Account, makes that PIN a requirement for registering your number on another phone. If you do not use Signal for seven days, the lock lapses, so the PIN protects an account you use, and an abandoned number can be registered again after a week.
By default Signal hides your number from anyone who does not already have it saved. Since 2024 you can set a username and let people reach you without ever seeing the number. The number is still how the account is registered and recovered.
What does this mean for an account on a second number?
People register a messenger on a second number to keep work and personal chats apart or to run a business account. If that number is a SIM you keep, nothing changes. If it was a rented number that returns to the pool after the activation, the lock settings decide whether the account stays yours.
- Set the app’s PIN or password straight after registering. On WhatsApp, two-step verification. On Telegram, the cloud password plus a recovery email. On Signal, Registration Lock.
- Keep the account signed in. Telegram codes go to existing sessions first, so a second device signed in, such as the desktop app, means future logins never need the number. WhatsApp and Signal need a new code only when you register on a new phone.
- Expect to lose the account if you reinstall without a backup and the number is gone. A re-registration needs a code sent to the number, and no lock setting changes that.
The second Telegram account guide walks through the Telegram case step by step. For WhatsApp, see how to verify WhatsApp without your own number.
Why do messengers rely on the number at all?
A phone number costs money and takes effort to get in bulk, which slows down mass account creation. It also gives the apps contact discovery, so your address book shows who is already on the app. WhatsApp and Telegram also check the line type and refuse many internet calling numbers, as covered in why services block VoIP numbers.
Common questions
Can I use the same number on WhatsApp, Telegram and Signal at once?
Yes. Each app keeps its own registration, so one number can hold one account on each.
Does a new owner of my old number get my chats?
No. Chats are stored on your devices or, on Telegram, in your account, and registering the number does not restore them for someone else. They can, however, register a new account on the number, or take over yours if it has no PIN or password.
Why did Telegram not text me the code?
Because you are signed in somewhere else. Open Telegram on that device and look for a message from Telegram. If there is no other session, wait for the timer and choose the SMS option.