mqtt5

MQTT v5.0 and v3.1.1 client and broker for native platforms (Linux, macOS, Windows).

Features

• MQTT v5.0 and v3.1.1 protocol support
• Multiple transports: TCP, TLS, WebSocket, QUIC
• QUIC multistream support with flow headers
• Automatic reconnection with exponential backoff
• Configurable keepalive with timeout tolerance
• Mock client for unit testing

Usage

Client (TCP)

use mqtt5::{MqttClient, ConnectOptions};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = MqttClient::new("client-id");
    let options = ConnectOptions::new("client-id".to_string());

    client.connect_with_options("mqtt://localhost:1883", options).await?;
    client.publish("topic", b"message").await?;
    client.disconnect().await?;

    Ok(())
}

Client (QUIC)

use mqtt5::{MqttClient, ConnectOptions};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = MqttClient::new("quic-client");

    // QUIC transport with built-in TLS 1.3
    client.connect("quic://broker.example.com:14567").await?;
    client.publish("sensors/temp", b"25.5").await?;
    client.disconnect().await?;

    Ok(())
}

Keepalive Configuration

use mqtt5::{MqttClient, ConnectOptions, KeepaliveConfig};
use std::time::Duration;

let options = ConnectOptions::new("client-id")
    .with_keep_alive(Duration::from_secs(30))
    .with_keepalive_config(KeepaliveConfig::new(75, 200));

The KeepaliveConfig controls ping timing and timeout tolerance:

• ping_interval_percent: When to send PINGREQ (default 75% of keep_alive)
• timeout_percent: How long to wait for PINGRESP (default 150%, use 200%+ for high-latency)

Broker

use mqtt5::broker::{MqttBroker, BrokerConfig};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut broker = MqttBroker::bind("0.0.0.0:1883").await?;
    broker.run().await?;
    Ok(())
}

Broker with Authentication

use mqtt5::broker::{BrokerConfig, AuthConfig, AuthMethod};

let config = BrokerConfig::default()
    .with_auth(AuthConfig {
        allow_anonymous: false,
        password_file: Some("passwd.txt".into()),
        auth_method: AuthMethod::Password,
        ..Default::default()
    });

Authentication methods: Password, SCRAM-SHA-256, JWT, Federated JWT (Google, Keycloak, etc.)

See Authentication & Authorization Guide for details.

Transport URLs

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.