How to scan for BLE devices with Kable?

Use the Scanner builder with filters, such as `Scanner { filters { match { name = Filter.Name.Exact('MyDevice') } } }`, which provides an advertisements Flow. Scanning starts when the Flow is collected and stops on termination, allowing for configurable scanning as shown in the README.

Kable vs Android BLE API: which is better for my app?

Choose Kable if you're building cross-platform Kotlin apps and want shared BLE logic with a modern Coroutines API. Opt for the native Android BLE API if your app is Android-only and needs direct access to platform-specific optimizations or advanced BLE features not abstracted by Kable.

How to handle BLE characteristic notifications in Kable?

Use the `observe` function on a characteristic, which returns a Flow of data changes. Collect from this Flow to process notifications, and it automatically reconnects after disconnections. You can also specify an onSubscription action for initial I/O operations upon subscribing.

Does Kable support background BLE operations on iOS?

Yes, but you must configure CentralManager with `stateRestoration = true` before using Kable, as mentioned in the Background Support section. This enables the app to handle BLE events in the background, but configuration must occur early to avoid IllegalStateException.

What Android permissions are needed for Kable?

Kable doesn't declare any permissions; your app must add them in the manifest, such as BLUETOOTH and BLUETOOTH_ADMIN. An optional artifact `kable-default-permissions` is available for common use cases, but you still need to manage permissions based on your requirements.

Can I use Kable for Web Bluetooth in all browsers?

No, Kable's JavaScript support relies on Chrome 79+ with 'Experimental Web Platform features' enabled, as noted in the README. This limits compatibility and makes it risky for production web apps that need stable, cross-browser BLE functionality.

Kable — Kotlin Coroutines BLE Library

What is Kable?

Kable is a Kotlin Multiplatform library that provides an asynchronous, Coroutines-based API for Bluetooth Low Energy (BLE) communication. It solves the problem of writing cross-platform BLE code by abstracting platform-specific details and offering a unified, modern API for scanning, connecting, and performing I/O operations with BLE devices.

Target Audience

Kotlin developers building cross-platform applications that need to communicate with BLE devices, such as IoT apps, health/fitness trackers, or smart device controllers on Android, iOS, web, and desktop.

Value Proposition

Developers choose Kable for its seamless integration with Kotlin Coroutines, eliminating callback hell and simplifying async BLE operations. Its multiplatform support reduces code duplication, while its idiomatic Kotlin API makes BLE development more intuitive and maintainable compared to platform-specific SDKs.

Kotlin Asynchronous Bluetooth Low-Energy

Use Cases

Best For

Building cross-platform mobile apps that connect to BLE sensors or wearables
Developing IoT applications that communicate with BLE-enabled smart devices
Creating health/fitness apps that read data from BLE heart rate monitors or glucose meters
Prototyping BLE interactions quickly using Kotlin Coroutines and Flows
Writing shared BLE logic for Android and iOS apps with a single codebase
Implementing Web Bluetooth functionality in Kotlin/JS applications

Not Ideal For

Native Android or iOS apps requiring direct, low-level access to platform-specific BLE APIs for performance-critical optimizations
Web projects targeting browsers without Web Bluetooth support or needing stable, non-experimental APIs for production use
Teams that rely on BLE scanning filters like Address on Apple platforms, where Kable lacks native support and uses less efficient flow filtering

Pros & Cons

Pros

Modern Coroutines API

Uses Kotlin Coroutines and Flows for all asynchronous operations like scanning and I/O, eliminating callback hell and making BLE code more readable and maintainable, as demonstrated in the SensorTag sample app.

Cross-Platform Abstraction

Abstracts platform-specific BLE complexities, allowing developers to write shared code for Android, iOS, JavaScript, macOS, and JVM with a consistent API, reducing code duplication across targets.

Flexible UUID Handling

Provides utilities like `Bluetooth.BaseUuid + 0x180D` and `Uuid.service('heart_rate')` for shorthand UUID notation, simplifying common BLE identifier management as outlined in the UUIDs section.

Built-in Connection Management

Handles connectivity with state flows, automatic service discovery, and support for reconnection, reducing boilerplate—examples include the `connect` and `disconnect` functions with automatic state transitions.

Cons

Platform Filter Inconsistencies

Some scanning filters, such as Address on Apple and JavaScript platforms, are not natively supported, forcing Kable to use less efficient flow filtering, which can impact scanning performance on those targets.

Web Bluetooth Limitations

JavaScript support depends on Chrome's experimental Web Bluetooth API, requiring users to enable flags like 'Experimental Web Platform features,' making it unsuitable for production web apps needing broad browser compatibility.

Setup Complexity

Requires Gradle configuration with Kotlin Multiplatform and Coroutines dependencies, plus platform-specific permissions and CentralManager setup for background support, which adds overhead for developers new to this ecosystem.

What is Kable?

Target Audience

Value Proposition

Use Cases

Best For

Building cross-platform mobile apps that connect to BLE sensors or wearables
Developing IoT applications that communicate with BLE-enabled smart devices
Creating health/fitness apps that read data from BLE heart rate monitors or glucose meters
Prototyping BLE interactions quickly using Kotlin Coroutines and Flows
Writing shared BLE logic for Android and iOS apps with a single codebase
Implementing Web Bluetooth functionality in Kotlin/JS applications

Not Ideal For

Native Android or iOS apps requiring direct, low-level access to platform-specific BLE APIs for performance-critical optimizations
Web projects targeting browsers without Web Bluetooth support or needing stable, non-experimental APIs for production use
Teams that rely on BLE scanning filters like Address on Apple platforms, where Kable lacks native support and uses less efficient flow filtering

Pros & Cons

Pros

Modern Coroutines API

Cross-Platform Abstraction

Abstracts platform-specific BLE complexities, allowing developers to write shared code for Android, iOS, JavaScript, macOS, and JVM with a consistent API, reducing code duplication across targets.

Flexible UUID Handling

Provides utilities like `Bluetooth.BaseUuid + 0x180D` and `Uuid.service('heart_rate')` for shorthand UUID notation, simplifying common BLE identifier management as outlined in the UUIDs section.

Built-in Connection Management

Cons

Platform Filter Inconsistencies

Web Bluetooth Limitations

Setup Complexity

Kable

What is Kable?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Found a gem we're missing?

Kable

What is Kable?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Found a gem we're missing?