# What is an NFC tag? How they work & program one — Taproo > An NFC tag is a tiny chip you tap with a phone to trigger an action. Learn what they are, how to program and scan them, and what to do if one won't read. Source: https://www.taproo.com/help/what-is-an-nfc-tag Help Centre · NFC basics # What is an NFC tag? An NFC tag is a small passive chip and antenna that stores a short piece of data, usually a URL. An NFC-capable phone powers and reads the tag at close range, so a tap can open a web page without the tag needing a battery. ## What is an NFC tag? An NFC tag is a small, battery-free chip in a sticker, card or keyring. It stores a short link or contact details and hands them to any phone held within about 4 cm — no app needed. - No batterypassive; powered by the phone's own field. - Rangeabout 4 cm — tap, don't wave. - Storesa URL, vCard, phone number or Wi-Fi credentials. - Common chipsNTAG213, NTAG215, NTAG216. - Phone supportmodern NFC-capable iPhones and Android phones can read standard URL tags; behaviour varies by model and settings. - Rewritablere-written thousands of times, or locked. Point it at a Taproo short link and change the destination later without re-writing the chip. On this page What an NFC tag isHow NFC worksHow to program oneHow to scan oneTroubleshootingFAQs ## What an NFC tag actually is NFC stands for Near Field Communication — a short-range wireless standard that lets two devices exchange data when they're held within about 4 cm of each other. An NFC tag is the passive half of that exchange: a postage-stamp-sized chip with a thin copper antenna, no battery, and a few hundred bytes of memory. When an NFC-capable phone comes near the tag, the phone's antenna induces a small current in the tag's coil — enough to power it briefly and read its data. That data is almost always a URL, which the phone opens automatically. You'll find NFC tags inside contactless bank cards, hotel key cards, transit passes, ski passes, festival wristbands, pet ID tags, business cards, and luggage labels. Anywhere you'd stick a QR code, you can use an NFC tag instead — and a tap is faster than aiming a camera. ## How NFC works (in 30 seconds) - 1. Power. Your phone's NFC antenna emits a 13.56 MHz radio field. The tag's coil absorbs just enough energy to wake up — no battery required. - 2. Handshake. The tag sends back its UID and stored payload (usually an NDEF record containing a URL). - 3. Action. Your phone's OS recognises the record type and opens the appropriate app — Safari/Chrome for a URL, Settings for Wi-Fi, Contacts for a vCard. The whole exchange takes 100–200 ms. Because NFC has a maximum range of about 4 cm, it's almost impossible to trigger by accident — your phone has to physically touch (or near-touch) the tag. ## How to program an NFC tag (5 steps) - ### 1. Pick the right tag For common NTAG21x tags, NTAG213 provides 144 bytes of user memory, NTAG215 504 bytes and NTAG216 888 bytes. A short URL usually needs little space; choose a tag that suits the payload and the devices you need to support. - ### 2. Decide what should happen on tap Most people encode a URL — a vCard page, a Wi-Fi join page, a menu, a review prompt, or a feedback form. With Taproo you point the tag at a dynamic destination so you can change what it does later without re-encoding the chip. - ### 3. Write the tag Open an NFC writer app (NFC Tools on Android, NFC Tools or Shortcuts on iPhone), choose 'Write → URL/URI', paste your link, then hold the phone steady against the tag for 1–2 seconds until you see a confirmation. - ### 4. Test before you deploy Lock the screen, then unlock and tap your phone against the tag. iPhone shows a banner; Android opens the link directly. If nothing happens, re-write the tag and check the antenna alignment. - ### 5. Lock the tag (optional) If the tag will live somewhere public — a poster, a product, a pet collar — use your writer app to lock it read-only so nobody can overwrite your link. Skip the writing step entirely. Compatible NFC products from the Taproo shop ships pre-encoded with a dynamic Taproo link. Change the destination from your dashboard at any time — the tag itself never needs to be re-written. ## How to scan an NFC tag ### iPhone iPhone XS and newer read tags in the background. Unlock the phone and hold the top-back of the device against the tag. iPhone 7, 8 and X need the NFC Tools app open. ### Android Most Android phones (Android 10+) read tags from the lock screen. Hold the back-centre of the device against the tag. Make sure NFC is enabled in Settings → Connections. ## When a tag won't read - Antenna miss. Slide the phone slowly around the tag. Different phones have the NFC coil in different places. - Metal interference. A tag stuck directly to metal won't read — use an on-metal tag with a built-in ferrite shield. - Wrong record type. iPhones only auto-launch URI/URL records. If your tag was written as plain text, re-write it as a URL. - NFC turned off. On Android, check Settings → Connections → NFC. iPhones can't disable NFC system-wide, but some focus modes suppress the banner. ## Frequently asked questions ### What is an NFC tag in simple terms? ### Do I need an app to scan an NFC tag? ### How do I program an NFC tag? ### How do I scan an NFC tag? ### Why won't my NFC tag read? ### Can I lock an NFC tag so nobody can overwrite it? ### Are NFC tags safe? ### Will an NFC tag work through a phone case? ## Ready to build one? Pick a use case Explore Taproo pages and NFC use cases, then choose compatible hardware where available. Digital business card →Guest Wi-Fi tap →Menu & table talker → See all 13 use cases → ## Get an NFC tag that you can re-target any time Every Taproo tag ships pre-encoded with a dynamic destination — change what it does from your dashboard, no re-writing required. Browse NFC tagsBack to Help Centre