URI Record

What Is an NDEF URI Record?

An NDEF URI recordURI recordNDEF record encodingencodingData writing to NFC tags during manufacturing productionView full → URIs with compact prefix compressionView full → (TNF 0x01, Well-Known Type "U") encodes a Uniform Resource Identifier — a web URL, telephone number, email address, or other URI-scheme resource. URI records are the most common NDEF type in deployed NFC tags. When a smartphone reads one, the OS automatically opens the URL, dials the number, or launches the appropriate handler without requiring a user-installed app.

URI Prefix Compression

The first payload byte is a URI Identifier Code representing a common prefix:

The NFC ForumNFC ForumIndustry body developing NFC standards, specifications, and certifications since 2004View full → defines 36 prefix codes (0x01-0x23). Code 0x00 stores the full URI as-is.

Memory Example

Storing https://example.com/product/12345: - Without compression: 37 bytes URI + 5 bytes overhead = 42 bytes - With code 0x04: 1 byte code + 29 bytes remainder + 5 bytes overhead = 35 bytes

On NTAG 213 (144 bytes user memory), this 7-byte saving represents nearly 5% of total capacity.

Payload Format

[URI Identifier Code: 1 byte] [URI Field: variable]

The complete URI is reconstructed by concatenating the prefix from the code lookup with the URI field. Code 0x00 means the URI field contains the full URI including scheme.

Platform Behavior

Android: Creates an ACTION_VIEW intent with the URI. If an AAR follows in the same NDEF message, the intent targets the specified app.

iOS: Displays a notification on iPhones with background tag reading (XS+). Tapping opens the URL in Safari or the associated universal link app.

Best Practices

• Use HTTPS (code 0x04) — browsers flag HTTP as insecure; iOS may block non-HTTPS.
• Shorten URLs for long addresses to conserve user memory.
• Combine with Smart Poster for marketing tags needing human-readable titles.
• Use SDM-enabled chips for authenticationauthenticationIdentity verification of NFC tags/readers via passwords or cryptographyView full → tags with dynamic URL parameters.