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Bluetooth-powered mesh messaging SDK for iOS, watchOS, tvOS, and macOS
Swift Objective-C
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Sources Apply fixes for handling configuration changes of remote services Feb 14, 2020
Tests Apply fixes for handling configuration changes of remote services Feb 14, 2020
.gitignore First commit Sep 30, 2019 Create Feb 2, 2020
Package.swift Update supported watchOS platform version Feb 14, 2020

Berkanan SDK

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Berkanan SDK enables Bluetooth-powered mesh messaging between nearby apps. It's the framework used by Berkanan (Product Hunt, TechCrunch) and Berkanan Lite (GitHub).

With Berkanan SDK, apps can discover nearby apps, which also have the SDK integrated, and send them small messages via Bluetooth. The range is about 70 meters, but they can reach further because the SDK automatically resends them upon receiving. The more apps use Berkanan SDK, the further the reach of the messages gets.

Features and Limitations

  • Free and open-source: Contributions are welcome!
  • Bluetooth-powered: No need for Wi-Fi or cellular connectivity.
  • Background: On iOS, it works even while in the background.
  • Connectionless communication with no pairing, no sessions, and no limit on the number of apps.
  • For sending messages, the SDK uses flooding, where duplicates are filtered by tracking their identifiers and decreasing their time to live (TTL) by 1, until they reach 0, as they travel from app to app.
  • The message range limit between two devices is about 70 meters.
  • The data size limit is 512 bytes.
  • No built-in support for encryption, acknowledgment, or store and forward. You have to roll your own if your use case requires it.
  • Supported operating systems: iOS 9.0 or later, watchOS 4.0 or later, tvOS 9.0 or later, macOS 10.13 or later.

Privacy Policy

Berkanan SDK does not send the messages to any central server or company — this can be verified by looking at its source code. If your app's messages contain sensitive information (e.g., a private text message), you should use encryption.

Integrating Berkanan SDK into your app


To integrate Berkanan SDK into your iOS app, use Xcode 11 or later. Open the .xcodeproj or .xcworkspace file of your app and follow these steps.

Configuring your app target

Select your app target and then go to Editor / Add Capability / Background Modes. Check both Uses Bluetooth LE accessories and Acts as a Bluetooth LE accessory.

Go to Signing & Capabilities / App Sandbox and check the Bluetooth checkbox.

Add NSBluetoothAlwaysUsageDescription and NSBluetoothPeripheralUsageDescription to the Info.plist with the value:

Allow access to the Berkanan Bluetooth Service to be able to communicate even while offline.

Adding Berkanan SDK to your app

Go to File / Swift Packages / Add Package Dependency... and enter

Add @import BerkananSDK to your source files where needed.

Using Berkanan SDK in your app

Initializing a local service with a configuration to advertise
let configuration = Configuration(
  // The identifier is used to identify what kind of configuration the service has. 
  // It should be the same across app runs.
  identifier: UUID(uuidString: "3749ED8E-DBA0-4095-822B-1DC61762CCF3")!, 
  userInfo: "My User Info".data(using: .utf8)!
// Throws if the configuration is too big or invalid.
let service = try BerkananBluetoothService(configuration: configuration)
Starting a local service
Discovering nearby services and their advertised configuration
let discoverServiceCanceller = service.discoverServiceSubject
  .receive(on: RunLoop.main)
  .sink { service in
    print("Discovered \(service) with \(service.getConfiguration())")
Constructing a message with a payload type identifier and payload
let message = Message(
  // The payloadType is used to identify what kind of payload the message carries.
  payloadType: UUID(uuidString: "E268F3C1-5ADB-4412-BE04-F4A04F9B3D1A")!,
  payload: "Hello, World!".data(using: .utf8)
Sending a message
// Throws if the message is too big or invalid.
try service.send(message)
Receiving messages
let receiveMessageCanceller = service.receiveMessageSubject
  .receive(on: RunLoop.main)
  .sink { message in
    print("Received \(message.payloadType) \(message.payload)")
Stopping the service

Sample app

To see how Berkanan Lite app integrates Berkanan SDK, check out its source code.

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