Before you print
How big should it be?
Rule of thumb: printed width ≥ scanning distance ÷ 10. Pick the surface above and the studio sizes the code for you, then checks the printed module size against what a press can actually hold.
Questions people actually ask
The code opens t.me/yourusername — if Telegram is installed it jumps straight to your profile with a message button; otherwise it shows a web preview with a link to get the app.
Yes — the link uses your public @username, not your phone number, so your number stays private. Set a username in Telegram under Settings before making the code (5–32 letters, digits, and underscores).
Yes — public channels, groups, and bots all have usernames, and their t.me links work exactly the same way. Paste the username with or without the @.
Never — it is just your t.me link encoded as squares, generated free in your browser with no signup. It keeps working for as long as the username exists, but if you change your username the old code stops resolving.
Want the detail? How telegram QR codes work — the payload format, what scanners do with it, and where it breaks.