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
WhatsApp opens with a chat to your number and your message prefilled — the scanner just taps send. If they do not have WhatsApp installed, the link opens in the browser and offers it.
WhatsApp identifies accounts by full international number, so the country code is required — +14155552671, not just 4155552671. The + and spaces are stripped automatically; without the right country code the chat simply will not open.
No — that is the magic. The code opens the chat directly without them saving your contact first, which is why these work so well on shop windows, menus, and support desks.
The code is generated in your browser, free with no signup — we never see it. But the number is encoded in the code itself, so anyone who scans can read it. Use a business number if you would rather keep your personal one private.
Want the detail? How whatsapp QR codes work — the payload format, what scanners do with it, and where it breaks.