GATT UUID Lookup

Every service, characteristic, and descriptor in a GATT database is identified by a UUID. A client uses those identifiers to discover a device's capabilities and address the attributes it needs to read, write, or subscribe to.

Adopted Bluetooth services use compact assigned numbers such as Heart Rate 0x180D, Battery 0x180F, and Device Information 0x180A. Product-specific profiles typically use full 128-bit UUIDs defined by the vendor or development team.

The Bluetooth SIG maps 16- and 32-bit assigned numbers into a shared 128-bit namespace using the Bluetooth Base UUID:

0000xxxx-0000-1000-8000-00805F9B34FB

Battery Service 0x180F, for example, expands to 0000180F-0000-1000-8000-00805F9B34FB. These are equivalent representations of the same identifier, which is important when comparing scanner output, API logs, and firmware constants.

BLE transmits multi-byte UUID values in little-endian order. That means0x180F appears on air as 0F 18, while a 128-bit UUID appears in reverse byte order relative to its canonical string. The lookup reports both forms for direct comparison with packet data.

Adopted service UUIDs identify standardized Bluetooth profiles. When a device exposes Heart Rate 0x180D, the adopted specification defines the expected service behavior and characteristic model.

Member assignments are allocated to an organization for company-defined use, such as Google 0xFEAA for Eddystone or Nordic 0xFE59for Secure DFU. The assignment identifies the owner; the owner's documentation defines the payload or GATT schema.

Proprietary protocols and vendor reference designs use 128-bit UUIDs outside the Bluetooth SIG assigned-number tables. Nordic UART Service, identified by 6E400001-B5A3-F393-E0A9-E50E24DCCA9E, is a widely deployed example. TI OAD and Microchip Transparent UART follow the same pattern.

These identifiers often remain stable for years because deployed firmware and applications depend on them. The lookup recognizes a curated set of common vendor services and characteristics while still validating any well-formed custom UUID.

• Advertising service lists and service data, including AD types 0x02, 0x03, and 0x16. The BLE Advertisement Decoder can inspect these fields directly.
• GATT discovery output from diagnostic applications and production software.
• Firmware constants, generated service definitions, and integration logs.
• Packet captures and HCI traces, where byte order may differ from the canonical representation used in documentation.

Start with the canonical UUID, confirm whether it is adopted, member-assigned, or vendor-defined, and then compare its on-air byte order before diagnosing a mismatch.