[](https://www.nuget.org/packages/MQTTnet)
[](https://bettercodehub.com/)
# MQTTnet
MQTTnet is a .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker). The implementation is based on the documentation from http://mqtt.org/.
# Features
### General
* Performance optimized (publishing ~18.000 messages per second on local machine)
* Async support
* TLS 1.2 support for client and server (but not UWP servers)
* Extensible communication channels (i.e. In-Memory, TCP, TCP+TLS, WS)
* Interfaces included for mocking and testing
* Lightweight (only the low level implementation of MQTT, no overhead)
* Access to internal trace messages
* Unit tested (55+ tests)
### Client
* Rx support (via another project)
* Communication via TCP (+TLS) or WS (WebSocket)
### Server (broker)
* List of connected clients available
* Supports connected clients with different protocol versions at the same time
* Able to publish its own messages (no loopback client required)
* Able to receive every messages (no loopback client required)
* Extensible client credential validation
# Supported frameworks
* .NET Standard 1.3+
* .NET Core 1.1+
* .NET Core App 1.1+
* .NET Framework 4.5.2+ (x86, x64, AnyCPU)
* Universal Windows (UWP) 10.0.10240+ (x86, x64, ARM, AnyCPU)
# Supported MQTT versions
* 3.1.1
* 3.1.0
# Nuget
This library is available as a nuget package: https://www.nuget.org/packages/MQTTnet/
# Contributions
If you want to contribute to this project just create a pull request.
# References
This library is used in the following projects:
* MQTT Client Rx (Wrapper for Reactive Extensions, https://github.com/1iveowl/MQTTClient.rx)
* HA4IoT (Open Source Home Automation system for .NET, https://github.com/chkr1011/HA4IoT)
If you use this library and want to see your project here please let me know.
# Examples
## MqttClient
```csharp
var options = new MqttClientOptions
{
Server = "localhost"
};
var client = new MqttClientFactory().CreateMqttClient(options);
client.ApplicationMessageReceived += (s, e) =>
{
Console.WriteLine("### RECEIVED APPLICATION MESSAGE ###");
Console.WriteLine($"+ Topic = {e.ApplicationMessage.Topic}");
Console.WriteLine($"+ Payload = {Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}");
Console.WriteLine($"+ QoS = {e.ApplicationMessage.QualityOfServiceLevel}");
Console.WriteLine($"+ Retain = {e.ApplicationMessage.Retain}");
Console.WriteLine();
};
client.Connected += async (s, e) =>
{
Console.WriteLine("### CONNECTED WITH SERVER ###");
await client.SubscribeAsync(new List
{
new TopicFilter("#", MqttQualityOfServiceLevel.AtMostOnce)
});
Console.WriteLine("### SUBSCRIBED ###");
};
client.Disconnected += async (s, e) =>
{
Console.WriteLine("### DISCONNECTED FROM SERVER ###");
await Task.Delay(TimeSpan.FromSeconds(5));
try
{
await client.ConnectAsync();
}
catch
{
Console.WriteLine("### RECONNECTING FAILED ###");
}
};
try
{
await client.ConnectAsync();
}
catch
{
Console.WriteLine("### CONNECTING FAILED ###");
}
Console.WriteLine("### WAITING FOR APPLICATION MESSAGES ###");
while (true)
{
Console.ReadLine();
var applicationMessage = new MqttApplicationMessage(
"A/B/C",
Encoding.UTF8.GetBytes("Hello World"),
MqttQualityOfServiceLevel.AtLeastOnce,
false
);
await client.PublishAsync(applicationMessage);
}
```
## MqttServer
```csharp
var options = new MqttServerOptions
{
ConnectionValidator = p =>
{
if (p.ClientId == "SpecialClient")
{
if (p.Username != "USER" || p.Password != "PASS")
{
return MqttConnectReturnCode.ConnectionRefusedBadUsernameOrPassword;
}
}
return MqttConnectReturnCode.ConnectionAccepted;
}
};
var mqttServer = new MqttServerFactory().CreateMqttServer(options);
mqttServer.Start();
Console.WriteLine("Press any key to exit.");
Console.ReadLine();
mqttServer.Stop();
```