When to use it
Customer support on packaging, a market stall or takeaway that takes orders by message, an estate agent’s board, a tradesperson’s van. WhatsApp is the default messaging app in much of the world, and a scan that opens a chat with “Hi, I’m interested in…” already typed lowers the barrier to getting in touch.
The payload shown above uses WhatsApp’s wa.me domain. The code on this page points at getqrstudio.app instead, because we never encode a real third party number on the site. Yours will use the wa.me pattern.
How it behaves on phones
iPhone: the Camera app shows a banner naming wa.me. Tapping it hands off to WhatsApp if installed, and the chat opens with the message in the box. If not installed, Safari shows a WhatsApp page.
Android: most Android scanners open the link and Android routes it straight to WhatsApp. Google Lens shows a preview first. Without the app, the browser opens.
Common mistake
Writing https://wa.me/+1 555 0100 or https://wa.me/05550100. The plus sign, spaces and leading zero all break the link, and the person sees “the phone number shared via url is invalid”. Digits only, starting with the country code.
Gotchas
Number format. Country code first, then the number without the trunk zero, digits only. This is the same as the international format used by tel: links, minus the plus sign.
Message encoding. Everything after ?text= must be percent encoded. Space is %20, a line break is %0A. A message such as “Hi, I saw your poster” becomes Hi%2C%20I%20saw%20your%20poster. QR Studio does this for you.
Length. The domain and number take about 22 characters. A short greeting keeps the whole payload under 60 characters, which fits version 4 at level M, 33 modules wide. A paragraph of pre-filled text can double that.
Group links. Invitation links to groups look like https://chat.whatsapp.com/... and are ordinary URLs. Anyone with the code can join, so think about where the poster goes.
Changing numbers. The number is baked into the code. If the business phone changes, every printed code breaks. A dynamic code that redirects to the wa.me link avoids the reprint.
Try it in QR Studio
QR Studio has a WhatsApp type with a number field and a message field. It strips the plus sign and spaces, encodes the message, and builds the wa.me link.
Print advice
Level M for shop windows and flyers, Q for a van or an outdoor sign where dirt and sun fade the print. A 5 cm code on a window is scanned from about half a metre; make it 10 cm if people will read it from the pavement. Put the number in plain text as well, with the WhatsApp name, so people can add you by hand.
Try it yourself
Enter a number and a greeting and see the encoded wa.me link the code will carry.