blew

blew is a BLE (Bluetooth Low Energy) Rust library focused on enabling peer-to-peer applications, and was built as the backend for iroh-ble-transport.

It differs from other libraries in that it implements both Central and Peripheral modes, and aims to provide support for macOS, iOS, Android, and Linux. It is also async-only and requires a Tokio runtime.

It also supports opportunistic L2CAP which provides a lower-level socket-type interface that tends to be significantly faster than using GATT for data transfer.

For Tauri users, see the companion crate tauri-plugin-blew that vastly simplifies the necessary setup of the Kotlin/JNI glue to enable Android functionality.

Supported Platforms

Examples

cargo run --example scan -p blew          # scan for 10s, print discoveries
cargo run --example advertise -p blew     # advertise a GATT service, handle reads/writes
cargo run --example l2cap_server -p blew  # peripheral: publish L2CAP CoC, echo data
cargo run --example l2cap_client -p blew  # central: scan, connect, open L2CAP, send data

Alternative Libraries

This library was customized primarily to be used for Iroh, and there are plenty of great alternatives out there! I'm sure I'm missing some, but to name a few that are actively maintained:

• btleplug
• bluest
• ble-peripheral-rust

License

This project is licensed under the GNU Affero General Public License v3.0 or later.

Commercial licenses are available for use cases where the AGPL is not suitable. Contact me@jakebot.org for details.