NDEF

NDEF (NFC Data Exchange Format)

NDEF is a lightweight data format defined by the NFC Forum for storing and exchanging structured data on HF RFID tags operating at 13.56 MHz. While EPC Gen2 defines the data architecture for UHF supply chain tags, NDEF is the standard for NFC-enabled tags used in consumer interaction, marketing, access control, and device pairing. It bridges the worlds of RFID infrastructure and smartphone-driven applications.

Message Structure

An NDEF message consists of one or more NDEF records, each carrying a typed payload:

The Type Name Format (TNF) field classifies the record type. The most common TNF values are:

• 0x01 (NFC Forum well-known): URI records, text records, smart poster records
• 0x02 (MIME media type): Arbitrary MIME payloads (vCard, JSON, etc.)
• 0x04 (NFC Forum external): Custom application-defined types

Common Record Types

URI Record: Stores a URL with a prefix compression scheme (e.g., 0x04 = https://). Tapping an NFC tag containing a URI record opens the URL in the smartphone browser. This is the backbone of NFC marketing tags, product authentication links, and Digital Product Passport access points.

Text Record: Contains a UTF-8 or UTF-16 string with a language code. Used for multi-language product information, Wi-Fi credentials, or plain-text messages.

Smart Poster Record: A container that wraps a URI record with optional title, icon, and action fields. Provides a richer tap experience than a bare URI.

NDEF on RFID Tags

NDEF data is stored in the User Memory area of ISO 14443 or ISO 15693 compatible tags. The NFC Forum defines tag type specifications (Type 1 through Type 5) that map NDEF storage to specific IC architectures:

• Type 2: Based on NXP NTAG family — most common for consumer NFC tags
• Type 4: Based on ISO 14443 — used in smart cards and higher-security applications
• Type 5: Based on ISO 15693 — enables longer read range and larger memory

NDEF and RFID Convergence

The rise of dual-frequency (UHF + NFC) tags creates interesting data architecture questions. A tag might carry an SGTIN in its UHF EPC Memory for supply chain singulation and an NDEF URI record in its NFC memory for consumer engagement. GS1 Digital Link provides the bridge — the NDEF URI can encode the same product identity as the EPC, enabling a single tap to access product information, authentication status, and sustainability data.