You have almost certainly used NFC today without thinking about it. Tapping a card on a reader to pay, tapping a phone on a turnstile, holding a hotel key card to a door — all of it is near-field communication. The same technology, in a much cheaper form, is what makes a tap-to-verify label or a digital business card work.
In one paragraph
NFC lets two devices swap a small amount of data when they are within a couple of centimetres of each other. An NFC tag is a tiny chip wired to a coil of aluminium or copper. It has no battery. A phone held nearby emits a magnetic field; the coil harvests enough energy from that field to wake the chip, which replies with the data it holds — normally a web address. The phone shows a notification, the person taps it, and the page opens. The whole thing takes under a second.
What NFC actually is
NFC stands for Near Field Communication. It is a set of radio standards operating at 13.56 megahertz, designed specifically so that two devices only talk when they are deliberately held close together. It grew out of RFID, which has been used for stock control and access badges since the 1980s, and it was standardised in the early 2000s by the companies behind contactless payment.
The important thing for anybody building something with it is that NFC is already in nearly every phone in your customers' pockets. You do not need to ship a reader, train anybody, or get an app installed. The reader is the one device your customer never leaves the house without.
How a tag works with no battery
This is the part that surprises people. An NFC tag is passive: it contains no power source of any kind and it is completely inert until a phone comes near it.
When an NFC-capable phone has its screen on, it is quietly generating a small alternating magnetic field and listening for a response. Bring a tag into that field and the tag's antenna — a flat spiral of conductive material, usually printed or etched — has a current induced in it. This is inductive coupling, exactly the same principle as a wireless phone charger, just at a far smaller scale. The induced current is tiny, but a modern NFC chip needs very little: enough to run for the few milliseconds it takes to reply.
The chip answers by changing how much energy it draws from the field, which the phone detects as a signal. It is a conversation conducted entirely in the phone's own energy budget.
The practical consequences matter:
- Nothing to charge. A tag glued to a wine bottle in 2026 will still work in 2036.
- Nothing to fail. No battery means no leak, no swelling, no disposal regulations.
- Nothing to switch on. The tag is always ready and draws nothing when it is not being read.
- Very cheap at volume. A basic inlay costs cents, which is why tagging an entire product line is realistic.
What is actually inside a tag
Peel the paper off an NFC label and you will find two components:
The antenna. A spiral of aluminium or copper, a few centimetres across, printed or etched onto a thin plastic film. Its size largely determines read distance — a credit-card-sized antenna reads from further away than a 12 mm disc.
The chip. A speck of silicon roughly the size of a grain of sand, bonded to the ends of the antenna. It holds a small amount of memory and a permanently burned-in serial number.
Together these two things are called an inlay. Everything else — the paper, the card, the resin, the adhesive — is just packaging around the inlay.
The chips most commonly used are the NXP NTAG series:
| Chip | Usable memory | Typical use |
|---|---|---|
| NTAG213 | ~144 bytes | The workhorse. A URL needs far less than this. Used for most labels and cards. |
| NTAG215 | ~504 bytes | When you need more records on the tag, or compatibility with certain toy and gaming ecosystems. |
| NTAG216 | ~888 bytes | Rare in marketing use. Worth it only when several records must live on the tag itself. |
These numbers look alarmingly small until you realise a tag should not hold your content. It holds a link. The content lives on a server, which is precisely what lets you change it later without touching the hardware.
What happens in that one second
Breaking the tap into its actual stages:
- Polling. The phone is already emitting its field and listening, several times a second.
- Energy transfer. The tag enters the field, the antenna induces a current, the chip powers up.
- Handshake. Phone and chip agree on a protocol and the chip transmits its unique identifier.
- Data transfer. The chip sends its stored NDEF record — a standard container format. For our purposes it holds a URL.
- Interpretation. The phone's operating system reads the record and recognises it as a web address.
- Notification. A banner appears showing the destination domain. Nothing opens automatically. The person always chooses.
- Browser. They tap the banner and the page loads over HTTPS in their normal browser.
Step six is worth dwelling on, because it is a deliberate safety design in both iOS and Android. A tag cannot launch an app, install software, make a payment or take any action on its own. The most a tag can do is suggest a web address. Everything after that is a normal, visible web interaction the person consented to.
Which phones can read NFC tags
The honest picture, as of 2026:
- iPhone XS, XR and every model since, on iOS 14 or later, read tags in the background. Unlock the phone, hold the top edge to the tag, tap the banner. No setup.
- iPhone 7, 8 and X have the hardware but not background reading. They can read a tag through the NFC Tag Reader in Control Centre or any free reader app.
- iPhone 6s and older cannot read tags at all. These phones use the printed QR code instead.
- Android has had broad NFC support for far longer. Essentially every mid-range and flagship phone since about 2015 includes it, enabled by default, reading from the lock screen on many models. Some budget handsets omit the hardware to save cost.
Put together, the large majority of phones in active use can tap. The minority that cannot is exactly why every product we ship carries a QR code and a short typed URL as well. Treating NFC and QR as rivals is a mistake; the sensible deployment ships both and lets the phone decide.
Range, and why it is short on purpose
The specification allows about four centimetres. In the real world — through a label, a card, a phone case — expect one to two.
People sometimes treat this as a weakness. It is the opposite. Short range means:
- A tag cannot be read from across a room, from a passing bag, or by somebody walking past you.
- Every read is unambiguously intentional, performed by the person holding the phone.
- Two tags next to each other do not interfere, because only one can be in the field at a time.
If you want something readable at distance you want a different technology — and you also want to think hard about the privacy implications of a tag that can be read without the owner knowing.
NFC vs RFID vs Bluetooth
| NFC | Passive RFID (UHF) | Bluetooth LE | |
|---|---|---|---|
| Range | 1–4 cm | Up to several metres | Up to ~50 m |
| Reader | Any modern smartphone | Dedicated hardware | Any smartphone |
| Power in the tag | None | None | Battery required |
| Setup for the user | None | Not consumer-facing | Pairing or an app |
| Unit cost | Cents | Cents | Dollars |
| Best at | Deliberate, one-to-one consumer interactions | Bulk inventory scanning | Continuous connection and sensing |
NFC is technically a short-range branch of RFID with two-way communication added. The practical dividing line is the reader: UHF RFID needs equipment, NFC needs a phone.
What stops a tag reading
Four things cause almost every failure, and all four are predictable before anything is printed.
Metal
A metal surface directly behind a standard inlay detunes the antenna and the tag goes dead. This affects tins, cans, foil pouches, blister packs and metal cards. The fix is an on-metal tag with a ferrite isolation layer between the antenna and the surface. This is the single most common reason a cheap NFC project fails in the field.
Placement and signposting
People do not search a package for an invisible chip. Mark the spot. A small tap symbol with two words of instruction dramatically raises first-attempt success.
Phone cases
Slim plastic, silicone and leather cases are fine. Thick wallet cases with card slots, and anything with a metal plate for a magnetic car mount, will block or badly weaken the field.
Antenna size
A small antenna reads only at very close range. If a tag must sit under a thick card or be found quickly, specify a larger inlay.
What people actually use it for
Beyond payments and transit, the consumer-facing uses that work are the ones where a tap replaces several fiddly steps:
- Proving a product is genuine and teaching the buyer how to use it, straight from the packaging.
- Sharing contact details without typing, and keeping them correct after a job change.
- Collecting reviews at the counter, while the customer is still in a good mood.
- Running an event — RSVP, directions, schedule and photos behind one printed card.
The pattern is the same every time: a physical object the person is already holding, one deliberate action, and a web page that does something genuinely useful at the other end.
