iOS & Android SMS URI prototype
Page URL — share this link or use it for QR codes:
On mobile, tap the green button to open your messaging app with the number and message prefilled. The QR code links to this page so it works from any QR scanner. The user must press Send — it will never auto-send.
How it works: The sms: URI scheme opens the default messaging app.
On iOS, Messages decides whether to use iMessage, RCS, or SMS based on the recipient.
The ?body= parameter prefills the message on most devices.
Apple docs don't officially support body prefill, but it works in practice on current iPhones.