One scan and their phone is already dialling.
Type your number. Download a code that opens the dialler with it filled in — no copying nine digits off a van in the rain, no transposing two of them.
More style options
Light grounds only — the code has to stay darker than what it sits on.
Six looks, made for being read in a hurry.
Pick one and it fills in the generator above. None of them carries a centre mark, which keeps the code plain enough to read at a distance.
Where these earn their keep
Vans and trade boards
Read from a moving vehicle or across a building site — the two places a number is most likely to be needed and least likely to be written down correctly.
Doors and shutters
Out of hours, or the office is on the fourth floor and the buzzer is broken. The code is the one thing at the door that still works.
Invoices and job sheets
The paperwork someone digs out three months later when the boiler goes again. A wrong digit on that page costs you the callback.
Questions people ask
Should I include the country code?
Yes, if anyone might scan it from abroad or from a foreign SIM — a leading plus and the country code work everywhere, while a local number works only locally. The generator keeps the plus and strips the spaces and brackets people type.
Does it ring immediately when scanned?
No, and it should not. The phone opens the dialler with the number in it and waits for a tap. Nobody's phone places a call because they pointed a camera at a wall, which is exactly right.
Can I use an extension?
Not reliably. Pause and wait characters are read differently by different phones, so a code with an extension in it works on some and not others. Point it at the main number and let the switchboard do its job.