What Is NFC?
Near-field communication (NFC) is a short-range wireless technology that enables two devices to exchange data when held within approximately 4 cm of each other. Built on decades of RFID research, NFC operates at 13.56 MHz and is the technology behind contactless payments, smart tags, and device pairing.
How NFC Works
NFC uses inductive coupling between two loop antennas. An active deviceactive devicePowered NFC device that generates its own RF fieldView full → — called an nfc-reader or initiator — generates a 13.56 MHz rf-field. When a passive nfc-tag enters this field, it harvests enough energy from the electromagnetic flux to power its chip and respond.
Data is exchanged at rates of 106, 212, or 424 kbit/s using ASK modulationASK modulationSignal amplitude variation encodingencodingData writing to NFC tags during manufacturing productionView full → data on 13.56 MHz carrierView full → and either Manchester or Modified Miller codingModified Miller codingBit encoding for NFC-A reader-to-tag communicationView full →. The entire transaction — from field detection to data exchange — completes in under 100 ms, which is why tapping feels instant.
NFC Operating Modes
The NFC Forum defines three operating modes that govern how NFC devices interact:
| Mode | Initiator | Target | Typical Use |
|---|---|---|---|
| Reader/Writer | Active | Passive tagPassive tagBatteryless tag powered by reader's electromagnetic fieldView full → | Reading product tags, writing URLs |
| Card Emulation | Reader | Phone/SE | Contactless payments, transit cards |
| Peer-to-Peer | Active | Active | Android Beam (legacy), pairing |
Reader/Writer modeReader/Writer modePrimary NFC mode: active device reads from or writes to passive tagView full → is the most common for IoT and product-labeling applications. Card emulation — backed by a secure-element or HCE — powers payment systems like Google Pay and Apple Pay.
NFC vs Other Wireless Technologies
| Feature | NFC | Bluetooth LE | Wi-Fi | QR Code |
|---|---|---|---|---|
| Range | ≤ 4 cm | ≤ 100 m | ≤ 100 m | Line-of-sight |
| Setup time | < 0.1 s | 2–6 s | 3–10 s | 1–3 s |
| Power (tag) | Passive | Active required | Active required | None |
| Data rate | 424 kbit/s | 2 Mbit/s | 600+ Mbit/s | N/A |
| Cost per unit | $0.05–$1 | $2–$10 | $3–$20 | ~$0 |
NFC's sub-4 cm range is a feature, not a limitation — it prevents accidental reads and ensures user intent. No pairing, no app install, no power source needed on the tag side.
The NFC Ecosystem
The NFC ForumNFC ForumIndustry body developing NFC standards, specifications, and certifications since 2004View full →, founded in 2004, defines the interoperabilityinteroperabilityCross-manufacturer device/tag compatibility guaranteeView full → standards that ensure a tag programmed on one device reads correctly on another. All certified devices must pass the nfc-forum-certification test suite. The operating-frequency of 13.56 MHz is globally license-free under ISM band regulations.
Use the NFC Chip Selector to find the right chip for your project, and the NFC Compatibility Checker to verify that your chosen tag will work with your target devices.
For a deeper dive into tag variants, see NFC Tag Types Explained.