EddystoneUID

EddystoneUID is a frame type defined by the Eddystone beacon format, a Bluetooth Low Energy (BLE) advertising protocol developed by Google. It broadcasts a globally unique identifier intended for proximity-based interactions and for linking physical beacons to backend systems, apps, or services. The UID frame is one of several frame types in the Eddystone specification, alongside URL, TLM, and EID frames, and is commonly used to identify a beacon or a group of beacons belonging to a given application or organization.

Frame structure and identifiers: An EddystoneUID advertisement carries a 16-byte identifier composed of a 10-byte Namespace ID (NID) and a 6-byte Instance ID (ID). The frame type for UID is 0x00, followed by a calibrated transmit power at 0 meters (TxPower), which is an 8-bit signed value used to help estimate distance to the beacon. The Namespace ID is intended to group beacons under a single application or entity, while the Instance ID distinguishes individual beacons within that namespace. The combination of NID and ID is designed to be globally unique.

Usage and considerations: UID frames enable applications to resolve a beacon to contextual data or actions provided by a backend. Because the identifiers are static, UID beacons can enable long-term tracking unless privacy-preserving measures are employed; for privacy-centric deployments, the Eddystone EID (Ephemeral ID) frame or rotating identifiers may be used. UID beacons are widely supported byBLE scanners and mobile platforms and are commonly deployed for asset tracking, proximity marketing, and indoor location-based services within organizations or venues.

See also: Eddystone protocol, Eddystone-URL, Eddystone-EID, Bluetooth Low Energy beacons.