NFC stands for Near Field Communication. The "near" part is the trick. Most wireless tech (Wi-Fi, Bluetooth, cell signals) is designed to broadcast outward in all directions, hopefully far. NFC is the opposite: it's designed to fail at any meaningful distance and only work when the two devices are essentially touching.
This isn't a bug. It's the entire point.
The two-second version
A blank NFC tag is a tiny coil of wire wrapped around a microchip the size of a pinhead. The chip is dead — it has no battery and stores no power. It just sits there, completely inert, for years.
When you tap your phone against the tag, the phone's NFC antenna sends out a short-range radio field. That field induces a tiny current in the tag's coil — enough to power the chip for the half-second the phone is nearby. While powered, the chip whispers a unique number back. Your phone reads the number, sees that it points to a URL, and opens that URL.
Then the field cuts out. The tag goes back to being inert. Total power consumed: a few microwatts, all donated by the phone.
Why this matters
No battery means it works forever. A car key fob has a battery and dies in 3 years. An NFC tag in a luggage strap has no battery and works in 30 years. The chip itself is rated for 100,000+ reads.
No broadcasting means privacy. A Bluetooth tracker is shouting "HERE I AM" 24/7. An NFC tag is silent unless something is touching it. No tracker fatigue. No anti-stalking alerts. No "your tag is leaking your location to anyone with a Bluetooth scanner" stories.
Standardized everywhere. The protocol is the same on every modern phone in the world. Apple, Google, Samsung, every Android — all of them speak it. There's no "this tag is incompatible with your phone." If the phone has tap-to-pay, it has NFC.
Cheap. The chips are made by the billion for things like contactless credit cards, transit passes, and event wristbands. A blank NFC sticker costs pennies. The cost of a Lochtag is the durable case and the printing, not the chip itself.
What's actually on the chip
A common NFC tag stores a single tiny piece of information: a URL. Like https://lochtags.com/t/A1EC7E24194F4A5D. That's it. About 30 characters.
When your phone reads it, the OS sees the URL, asks if you want to open it, and you get a normal web page. The web server on the other end sees the unique tag ID in the URL and decides what to show — for us, that's the lookup page for that specific tag, with the owner's contact options.
The chip itself doesn't know who owns the tag. It doesn't know the tag is "claimed" or "lost." All of that is on our server. The chip is just a unique fingerprint that points the phone at the right page.
Why "near" is important
The reason NFC range is roughly the thickness of a credit card is that the technology uses inductive coupling, not radio broadcasting. Think of two coils held next to each other. Pass current through one, and the magnetic field induces current in the other. Move them an inch apart and the induction collapses to almost nothing.
This is the same physics used in wireless phone chargers, electric toothbrush cradles, and contactless payment terminals. It's old, well-understood, and limited to almost-touching range by basic physics — not by software you could overcome.
For a lost-and-found use case, "near" is exactly what you want. A finder physically holds the tag next to their phone. Nobody can read your tag from across the parking lot. Nobody can scan your tag without you noticing.
What about RFID? Aren't those the same?
RFID is the broader family. NFC is a specific subset of RFID that operates at 13.56 MHz with two-way communication and standardized protocols. The contactless card on your transit pass is NFC. The little plastic tag stuck to a hotel-room key is usually NFC. The longer-range tag stuck to a pallet in a warehouse is a different RFID variant designed to be read from across the room.
For consumer lost-and-found, you specifically want the short-range, secure NFC variant. Long-range RFID would broadcast your tag to anyone with a scanner — exactly the wrong tradeoff.
The takeaway
NFC is unfashionably old technology that is, for a specific job, exactly the right tool. It's been in your transit card, your hotel key, your office badge, and your tap-to-pay credit card for over a decade. We're using it to solve a problem it's perfectly suited for: a privacy-respecting, no-battery, works-on-any-phone way to reunite people with their stuff.
That's it. There's no app to download, no account to create, no battery to worry about, no firmware to update. Stick the tag on your bag, register the URL, and the system runs forever.
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