# `MqttX`
[🔗](https://github.com/cignosystems/mqttx/blob/v0.9.0/lib/mqttx.ex#L1)

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 →](readme.html)**

## 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)

# `mqtt_version`

```elixir
@type mqtt_version() :: 3 | 4 | 5
```

# `packet_type`

```elixir
@type packet_type() ::
  :connect
  | :connack
  | :publish
  | :puback
  | :pubrec
  | :pubrel
  | :pubcomp
  | :subscribe
  | :suback
  | :unsubscribe
  | :unsuback
  | :pingreq
  | :pingresp
  | :disconnect
  | :auth
```

# `qos`

```elixir
@type qos() :: 0 | 1 | 2
```

# `topic`

```elixir
@type topic() :: binary() | [binary() | :single_level | :multi_level]
```

# `version`

```elixir
@spec version() :: String.t()
```

Returns the library version.

---

*Consult [api-reference.md](api-reference.md) for complete listing*