# Telegram QR codes — how they work

> A Telegram QR code is a t.me link to a username, channel, group or bot. Scanning it opens Telegram at that destination, or the web preview if Telegram is not installed. Usernames are 5–32 characters of letters, digits and underscores, and changing yours breaks every printed code.

Source: https://useqr.app/telegram-qr-code · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

---

## The payload

```
https://t.me/my_username
```

A plain HTTPS link. If Telegram is installed the app intercepts it; otherwise the
browser shows a preview page with an install prompt. That graceful fallback is why
`t.me` links are better on print than the `tg://` deep-link scheme, which shows an
error page when the app is missing.

## Username rules

5 to 32 characters, letters, digits and underscores only. No leading digit, no
consecutive underscores in some contexts. The `@` you see in the app is display sugar —
it is not part of the URL.

**Usernames are mutable.** If you rename the channel, every printed QR code stops
working, and the old username becomes available for someone else to claim. For anything
going to print, decide the username first and leave it alone.

## Link variants

| Destination | Link |
|---|---|
| User or channel | `t.me/name` |
| Private group invite | `t.me/+AbCdEf...` |
| Bot with a start parameter | `t.me/mybot?start=campaign1` |
| Specific message | `t.me/name/123` |

The bot `start` parameter is the interesting one for marketing: the value is passed to
the bot on first contact, so a QR code on a poster can tell the bot which poster it was.
That is offline attribution without any tracking of the user.

Private group invite links can be revoked, and a revoked link is dead everywhere. Do
not print one unless you accept that.

## FAQ

### What happens if the person does not have Telegram?
The t.me link opens a web preview page with a prompt to install the app. It fails gracefully, unlike the tg:// scheme which shows a browser error.

### Can I link to a private group?
Yes, with an invite link of the form t.me/+AbCdEf. Be aware that invite links can be revoked, which instantly breaks every printed copy.

### Can a QR code pass data to my Telegram bot?
Yes. Use t.me/yourbot?start=value — the value reaches the bot when the chat begins, which lets you attribute a scan to a specific poster or location without tracking the user.

### What happens if I change my username?
Every printed QR code breaks, and the old username becomes claimable by someone else. Fix the username before printing anything.

## Try it

- https://useqr.app/telegram
- https://useqr.app/whatsapp
- https://useqr.app/social