Bluetooth

Discover, connect to and exchange data with Bluetooth Low Energy and Classic accessories.

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Introduced

2011

iOS 5

Kind

Framework

Runs on

Get it from

iOS

5.0+

iPadOS

5.0+

Mac Catalyst

13.1+

macOS

10.7+

tvOS

9.0+

visionOS

1.0+

watchOS

2.0+

Overview

Core Bluetooth gives apps the classes they need to communicate with Bluetooth Low Energy and BR/EDR (Classic) devices. An app can act as a central that scans for, connects to and reads from peripherals, or as a peripheral that publishes services and advertises them to nearby centrals. L2CAP channels offer a stream-based path for larger data transfers.

AccessorySetupKit, added in iOS 18, presents a system picker with the accessory's name and image, so people can pair a Bluetooth or Wi-Fi accessory with one app without a broad Bluetooth permission prompt. In iOS 27, Channel Sounding lets apps measure the distance to supported accessories.

Central role

Scan for, connect to and read from Bluetooth Low Energy peripherals.

Peripheral role

Publish GATT services and advertise them from the app to nearby centrals.

Accessory setup

AccessorySetupKit pairs an accessory to one app through a system picker.

Channel Sounding

Measure the distance to supported Bluetooth LE accessories in iOS 27.

HeartRateScanner.swift

import CoreBluetooth

final class HeartRateScanner: NSObject, CBCentralManagerDelegate {
    private var central: CBCentralManager!

    override init() {
        super.init()
        central = CBCentralManager(delegate: self, queue: nil)
    }

    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        guard central.state == .poweredOn else { return }
        central.scanForPeripherals(withServices: [CBUUID(string: "180D")])
    }

    func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral,
                        advertisementData: [String: Any], rssi RSSI: NSNumber) {
        print("Found \(peripheral.name ?? "unnamed") at \(RSSI) dB")
    }
}

History