bjorkan/meshcore-mqtt-broker repository overview

⁠meshcore-mqtt-broker

A WebSocket-based MQTT broker with MeshCore public key authentication.

Docker image: bjorkan/meshcore-mqtt-broker

⁠Features

• WebSocket MQTT: Uses MQTT over WebSockets (not MQTT over TCP protocol)
• Public Key Authentication: Clients authenticate using their MeshCore public keys
• Topic Authorization: Controls access to meshcore/* topics

⁠Authentication

⁠Username Format

v1_{UPPERCASE_PUBLIC_KEY}

Example: v1_7E7662676F7F0850A8A355BAAFBFC1EB7B4174C340442D7D7161C9474A2C9400

⁠Password Format

The password is a JWT-style authentication token signed with your MeshCore Ed25519 private key using orlp/ed25519, which is used in the MeshCore firmware and in the @michaelhart/meshcore-decoder library's createAuthToken function.

import { createAuthToken } from '@michaelhart/meshcore-decoder';

const privateKey = 'YOUR_64_BYTE_PRIVATE_KEY_HEX'; // MeshCore format
const publicKey = 'YOUR_32_BYTE_PUBLIC_KEY_HEX';

const password = await createAuthToken(
  {
    publicKey: publicKey,
    aud: 'mqtt.yourdomain.com', // Must match AUTH_EXPECTED_AUDIENCE in .env
    iat: Math.floor(Date.now() / 1000),
    // Optional: add expiration
    // exp: Math.floor(Date.now() / 1000) + 3600 // 1 hour
  },
  privateKey,
  publicKey
);

The token format is: header.payload.signature where the signature is verified using Ed25519.

⁠Configuration

All configuration is done via environment variables in a .env file.

From this directory, copy .env.example to .env and configure:

cp .env.example .env

Edit .env:

# MQTT Server Settings
MQTT_WS_PORT=8883
MQTT_HOST=0.0.0.0

# Authentication Settings
# Expected audience claim in JWT tokens (leave empty to skip validation)
AUTH_EXPECTED_AUDIENCE=mqtt.yourdomain.com

# Subscribe-Only Users (read-only monitoring accounts)
# Format: SUBSCRIBER_N=username:password:role:maxConnections
# Role: 1=admin (full access + delete + PII), 2=full_access (no filtering), 3=limited (filtered)
# maxConnections: number for override, D or omit to use default
# Add as many as you need by incrementing the number
SUBSCRIBER_MAX_CONNECTIONS_DEFAULT=2
SUBSCRIBER_1=admin:your-secure-password-here:1:10
SUBSCRIBER_2=viewer:another-secure-password:2
SUBSCRIBER_3=monitor:yet-another-password:3:D
SUBSCRIBER_4=uplink:change-this-password:2:1

Subscribe-only users can read messages but cannot publish. They're useful for monitoring, debugging, and administrative dashboards.

The uplink subscriber is included for the bridge example in the repository root compose.yaml. If you change that user or password, update ../bridge/.env to match.

Subscriber Roles:

• Role 1 (Admin): Full access including /internal topics (contains PII), $SYS/* system topics, and ability to delete retained messages
• Role 2 (Full Access): Access to all public topics with no data filtering, cannot access /internal or $SYS/*
• Role 3 (Limited): Access to public topics only with sensitive data filtered (SNR, RSSI, score, stats, model, firmware_version removed from messages)

⁠Installation

# From the repository root:
cd broker
npm install

⁠Usage

⁠Development

npm run dev

⁠Production

npm run build
npm start

⁠Connecting Clients

⁠JavaScript/Node.js Example

const mqtt = require('mqtt');
const { createAuthToken } = require('@michaelhart/meshcore-decoder');

const privateKey = 'YOUR_64_BYTE_PRIVATE_KEY_HEX'; // MeshCore format
const publicKey = '7E7662676F7F0850A8A355BAAFBFC1EB7B4174C340442D7D7161C9474A2C9400';
const clientId = 'meshcore_test_client';

async function connect() {
  // Generate auth token
  const password = await createAuthToken(
    {
      publicKey: publicKey,
      aud: 'mqtt.yourdomain.com', // Must match AUTH_EXPECTED_AUDIENCE in .env
      iat: Math.floor(Date.now() / 1000),
      exp: Math.floor(Date.now() / 1000) + 86400 // 24 hours
    },
    privateKey,
    publicKey
  );

  const client = mqtt.connect('ws://localhost:8883', {
    clientId: clientId,
    username: `v1_${publicKey}`,
    password: password
  });

  client.on('connect', () => {
    console.log('Connected!');
    client.subscribe('meshcore/#');
  });

  client.on('message', (topic, message) => {
    console.log(`${topic}: ${message.toString()}`);
  });
}

connect();

⁠Topics

Publishers can only publish to topics with the following format:

• meshcore/{IATA_CODE}/{PUBLIC_KEY}/{subtopic}

Examples:

• meshcore/SEA/7E7662676F7F0850A8A355BAAFBFC1EB7B4174C340442D7D7161C9474A2C9400/packets
• meshcore/SEA/7E7662676F7F0850A8A355BAAFBFC1EB7B4174C340442D7D7161C9474A2C9400/status
• meshcore/PDX/7E7662676F7F0850A8A355BAAFBFC1EB7B4174C340442D7D7161C9474A2C9400/internal (ADMIN-only - contains PII)

Where:

• {IATA_CODE} must be a valid 3-letter IATA airport code (e.g., SEA, PDX, BOS) or test for testing
• {PUBLIC_KEY} must be the full 64-character hex public key (matching your authenticated public key)
• {subtopic} can be any subtopic name (e.g., packets, status, internal)

Important: The /internal subtopic is ADMIN-only and contains PII (Personally Identifiable Information) from JWT payloads. Only subscribers with role 1 (admin) can access these topics.

All published messages must be valid JSON and contain an origin_id field matching your authenticated public key. In the future, this requirement and the origin_id field may be removed, as they are a part of the MQTT session. For now, this is largely for backwards compatibility.

Subscribers (read-only users) can subscribe to any topic including wildcards like meshcore/#.

⁠Deployment

Use this directory as the Docker build context or application root.

docker build -t bjorkan/meshcore-mqtt-broker .

This project can also be deployed via Nixpacks (e.g., to Dokploy). Configure the app root/build path as broker/.

The build process will:

1. Install dependencies
2. Compile TypeScript to JavaScript
3. Run the compiled server

For setting up with TLS using Cloudflare Tunnels, see docs/cloudflare-tunnels.md⁠. This is the recommended way to deploy the MQTT broker.

⁠License

MIT. See ../LICENSE.md⁠.