SMS QR Codes: Pre-Filled Text Messages From a Scan

A link QR code opens a browser. A phone QR code opens a dialer, waiting for someone to decide what to say. An SMS QR code does both jobs at once: it opens the Messages app with the recipient and the message text already filled in, leaving nothing to type but the decision to hit send.

What actually gets encoded

Our generator writes an SMS code in the SMSTO: format — SMSTO:+12025550123:Hi, I would like to book a table for two. The first two colons are separators; any colon after that is just part of the message text. This is the older Denso Wave convention for SMS codes, and it remains the most broadly recognised format across both iPhone and Android camera scanners, which is why it is what most QR generators, ours included, default to.

There is also a newer standard, sms:, defined in RFC 5724, shaped like sms:+12025550123?body=Hi%2C%20I%20would%20like%20to%20book%20a%20table. Functionally the two do the same thing; the practical difference is that sms: requires the message body to be URL-encoded (spaces become %20, and so on), while SMSTO: carries the text plain. Both formats are natively understood by the stock camera apps on iOS and Android.

What happens after the scan

Scanning an SMS code does not send anything by itself. It opens the Messages app with the recipient and the draft text already in the compose field — the person still has to look at it and tap send, exactly like they would with a message they typed themselves. That visible, manual last step is what makes SMS codes trustworthy in a way a silent background action would not be: nothing leaves the phone without the person seeing it first.

Where this actually earns its place

SMS codes are most useful wherever the message is short, the number is fixed, and typing it out would be the main friction:

• Text clubs and specials. "Text JOIN to get weekly deals" becomes a single scan instead of a number to remember and a word to spell correctly.
• Property and rental signage. A yard sign that opens a pre-written "I'm interested in a tour" message removes an entire step between someone standing outside and a lead landing in your phone.
• Event RSVPs and waitlists. A printed table tent or door sign that drafts "Add me to the waitlist for tonight" turns a conversation with staff into a thirty-second scan.
• Support and warranty lines. A code on a product insert that opens a message to a support number, with the product name already filled in, saves the customer from hunting for a contact page.

Getting the number and message right

A few details decide whether the pre-filled message actually sends cleanly:

• Use the full international format. Include the country code (+1, +44, and so on) rather than a local-format number, so the code works correctly regardless of where the scanning phone is set up.
• Keep the message short. A long pre-filled draft is easy to misread as spam, and some older scanner apps truncate very long strings before they ever reach the Messages app.
• Avoid unusual punctuation. Stick to plain words and standard punctuation; some special characters behave inconsistently across scanner implementations.
• Test on both platforms before printing. Scan the code with an iPhone and an Android phone and confirm the number and text both arrive intact — the two platforms occasionally differ on edge cases.

For guidance on where to physically place a code like this so people actually stop and scan it, see where to put a QR code so people actually scan it. Build your own SMS code in the SMS QR code generator — the message updates in the live preview as you type.