MqttX — Fast, pure Elixir MQTT 5.0 — client, server, and codec in one package.

Key features:

• High-performance packet codec
• Transport-agnostic server/broker
• Modern client with automatic reconnection

See full documentation, installation guide, and examples →

Quick Start

Server

defmodule MyApp.MqttHandler do
  use MqttX.Server

  @impl true
  def handle_connect(client_id, credentials, state) do
    {:ok, Map.put(state, :client_id, client_id)}
  end

  @impl true
  def handle_publish(topic, payload, opts, state) do
    IO.inspect({topic, payload}, label: "Received")
    {:ok, state}
  end
end

# Start server
MqttX.Server.start_link(MyApp.MqttHandler, [],
  transport: :thousand_island,
  port: 1883
)

Client

{:ok, client} = MqttX.Client.connect(
  host: "localhost",
  port: 1883,
  client_id: "my_client"
)

:ok = MqttX.Client.subscribe(client, "sensors/#", qos: 1)
:ok = MqttX.Client.publish(client, "sensors/temp", "25.5", qos: 0)

Packet Codec

# Encode
packet = %{type: :publish, topic: "test", payload: "hello", qos: 0, retain: false}
{:ok, binary} = MqttX.Packet.encode(4, packet)

# Decode
{:ok, {decoded, rest}} = MqttX.Packet.decode(4, binary)

Protocol Versions

• MQTT 3.1 (version 3)
• MQTT 3.1.1 (version 4)
• MQTT 5.0 (version 5)