When you’re connected to the Thingy, you can check which Generic Attributes (GATT) services are available. There are a list of standardised services available in the Bluetooth spec, such as Battery Level, Heart Rate, Location and Navigation.

Besides the standardised services from the spec, BLE devices can feature their own services and characteristic definitions. The Nordic Thingy:52, for example, has the Weather station service. This service has several characteristics such as temperature, pressure and humidity.

A mobile phone/tablet/browser is a GATT Client and the BLE device (Thingy) is the GATT Server. The Client will always initiate the request to a GATT Server. GATT (Generic Attributes) defines a hierarchical data structure that is exposed to connected Bluetooth Low Energy (LE) devices.