Bluetooth Classic for Flutter

Discover, pair and exchange data with Bluetooth Classic devices over RFCOMM, the Serial Port Profile, from one Dart API.

Install#

flutter pub add flutter_classic_bluetooth

import 'package:flutter_classic_bluetooth/flutter_classic_bluetooth.dart';

Bluetooth Classic, not Bluetooth Low Energy#

This plugin speaks RFCOMM/SPP: the classic Bluetooth serial transport that ESP32 boards, HC-05 modules, barcode scanners, thermal printers and OBD-II adapters use. It is not a BLE plugin. If your device advertises GATT services and characteristics, you want a Bluetooth Low Energy package instead.

A connection is a plain byte stream. Reading and writing feels like any other Dart Stream and Sink.

Connect and talk to a device#

final bluetooth = FlutterClassicBluetooth();

final connection = await bluetooth.connect(
  address: 'AA:BB:CC:DD:EE:FF',
  uuid: BtcUuid.spp,
);

connection.input.listen((bytes) => print('RX ${bytes.length} bytes'));
await connection.output.writeString('AT');

await connection.finish();

Find a device first#

final devices = await bluetooth.scan(timeout: const Duration(seconds: 10));

for (final device in devices) {
  print('${device.displayName}  ${device.address}  ${device.rssi} dBm');
}

scan collects discovery results, deduplicates them by address and sorts by signal strength. For a live list that fills in as devices appear, listen to the discovery stream instead.

What it can do#

• Check and request the Bluetooth permissions each platform needs, with no extra package.
• Discover nearby devices and list the ones already paired.
• Connect over RFCOMM by MAC address and service UUID, then read and write bytes.
• Run an RFCOMM server that accepts incoming connections.
• Pair and unpair, toggle the adapter, and make the device discoverable, where the platform allows it.
• Reconnect automatically with a backoff policy when a link drops.
• Ask at runtime which of those the current platform actually supports.

Where it runs#

Rather than guessing, ask:

final caps = await bluetooth.getPlatformCapabilities();

if (caps.canDiscoverDevices) {
  // show the scan button
}

See the desktop guide for what differs on Windows, macOS and Linux.

Start here#

Set up permissions first, since nothing works without them on Android. Then scan, connect, and move some bytes. If you are wiring up a specific board, jump straight to ESP32, HC-05, or a thermal printer.