What happens to your NFC card when you change your phone number

Nobody buys a contact card thinking about the day their details change. But details change constantly. People switch networks, leave jobs, rebrand, move a landline, or finally give up the number they have had since sixth form. And the card you handed to forty people last year is still out there in wallets and van glove boxes, quietly telling all of them something that is no longer true.

What happens next depends on one thing, and it is not the price of the card or what it is made of. It is where the details are stored. There are three answers, and they are very different.

If the details are printed on the card

This is a paper business card, and everybody already knows the answer: you reprint. Five hundred cards go in the recycling, you order five hundred more, and for the next six months you keep finding old ones in coat pockets and handing them over with the number crossed out in biro.

The cards already in other people's hands are simply wrong, permanently, and there is nothing you can do about it. Most people accept this because paper is cheap. It is worth noticing that the cost was never the printing — it was the calls you never got.

If the details are written onto the chip

This is the part most buyers do not realise they are choosing, because from the outside it looks identical to any other NFC card.

A cheap NFC card is a blank chip with something written onto it — usually a web address, sometimes a vCard carrying your name and number directly. The seller encodes it once before posting it to you. That is why it can be sold for a few pounds: nothing happens after it leaves the warehouse, because there is nothing running behind it.

Which is fine, right up until the day something changes. Then the address on the chip still points exactly where it always pointed. To fix it you need the physical cards back in your hand, one at a time, to re-encode each one. The forty you have already handed out are unreachable. You cannot recall a business card.

Some sellers advertise their cards as reprogrammable, and it is worth understanding exactly what that means, because it sounds like the answer and is not. It means you can re-encode the chip yourself, with an app, while holding the card. It is a description of the blank chip, not of a service behind it. It does nothing whatsoever for a card that is in somebody else's wallet.

Reprogrammable means you can rewrite the card you are holding. It has never meant you can rewrite the card you gave away.

If the card is a key rather than a label

The third arrangement is the one we use, and the difference is small to describe and large to live with. The chip does not carry your web address, your name or your number. It carries a permanent code that means nothing on its own — and we hold the record of what that code opens.

So when your number changes, you sign in, edit your profile once, and every card you have ever handed out points at the new number from that moment. Not the ones in your drawer. All of them. The one in a customer's van from two years ago, the one in a wallet in another country, the one you have completely forgotten about.

Nothing is re-encoded and nothing comes back to you, because the thing that changed was never on the card in the first place.

• New mobile number: edit it once, in a browser.
• New job, new company, new email: same edit, same minute.
• Point a card at a completely different profile — useful when somebody leaves, or when a card was made for a role rather than a person.
• Lost a card: switch it off from your dashboard and it stops opening anything at all.

That last one is worth dwelling on. A card with your details written onto the chip keeps working perfectly for whoever picked it up, and there is no way to stop it. A card that is only a key can be taken off the keyring.

The same split applies to QR codes, and it catches people out

QR codes have exactly the same division, and because generating one is free, most people end up with the wrong kind without ever making a decision about it.

A free QR generator usually encodes the data into the pattern itself — your number is literally in the black and white squares. Print that on a van, a sign or a shop window and it is fixed there permanently. Change your number and the only fix is a new sign. Every card and stand we make carries a QR as well as a chip, and both point at the same permanent code rather than at the data, which is why a printed QR survives a change of number just as the chip does.

The QR matters for a second, more practical reason too: not every phone will tap. Older handsets and locked-down work phones read the code with the camera instead, and land in exactly the same place. More on how the QR side works.

The fair objection

If the card is a key and somebody else holds the lock, you are depending on that somebody still being there. That is a real dependency and it deserves a straight answer rather than a reassuring noise.

Our answer has three parts. The profile, the QR, the sharing and the analytics view are free and not on a subscription, so there is no monthly payment that can lapse and take your card down with it. Your data is yours and you can export it whenever you like, without paying for the privilege. And we make our money from cards and from an optional Pro tier rather than from your contacts, which is the part that decides how a company behaves when times get harder.

What we are not going to tell you is that no company ever disappears. What we will say is that the trade is a knowable one. A card with the address burned into the chip depends on nobody and can never be changed. A card that is a key can always be changed and depends on somebody being there. Most people, once they have actually lived through a number change, decide they would rather have the second problem.

And if you just want a cheap card

Then buy a cheap card, honestly. If what you want is a printed link to a page that is never going to move — a menu, a one-off event, a fixed listing — a few pounds for a pre-encoded chip is perfectly good value and we are not going to pretend otherwise.

The question worth asking before you buy anything is simply: what happens to this when something changes? If the answer is “reprint” or “get them all back first”, you now know why, and you can decide whether that matters for the way you actually trade. For plenty of people it genuinely does not. For anyone handing cards to customers they want to hear from again, it is the whole thing.

If you are weighing up materials and prices, the card range and what each one costs is on one page, and there is no subscription attached to any of it. If you would rather see how the profile behaves before buying anything at all, you can set one up for free and share it by QR today.