MessagePack serializer package

Package: Pulse.Mqtt.Serialization.MessagePack

Use this package when typed MQTT payloads should be compact binary messages and the application already owns MessagePack contracts or wants smaller payloads than JSON.

Install

dotnet add package Pulse.Mqtt.Serialization.MessagePack

Configure generated resolvers

Build MessagePackSerializerOptions with generated resolvers for the message types you publish and consume. The exact resolver setup depends on how the application generates MessagePack metadata, but the serializer expects the finished options object:

using MessagePack;
using MessagePack.Resolvers;
using Pulse.Mqtt.Serialization.MessagePack;

[MessagePackObject]
public sealed record TelemetryReading(
    [property: Key(0)] string DeviceId,
    [property: Key(1)] double Value);

var messagePackOptions = MessagePackSerializerOptions.Standard.WithResolver(
    CompositeResolver.Create(
        GeneratedMessagePackResolver.Instance,
        StandardResolver.Instance));

var serializer = new MessagePackMqttSerializer(messagePackOptions);

Prefer generated resolvers for trimming and Native AOT. Avoid contractless or reflection-heavy configuration in applications that publish with trimming enabled.

Configure with dependency injection

builder.Services
    .AddPulseMqttClient("telemetry", configure)
    .UseSerializer(_ => new MessagePackMqttSerializer(messagePackOptions));

Configure directly

var options = new ResilientMqttClientOptions
{
    Connect = new MqttConnectPacket { ClientId = "telemetry-worker" },
    Serializer = new MessagePackMqttSerializer(messagePackOptions),
};

Wire metadata

Typed publishes created with this serializer stamp:

Field	Value
ContentType	application/x-msgpack
PayloadFormatIndicator	Unspecified

Unspecified is intentional because the payload is binary, not UTF-8 text.

Use typed APIs

await client.PublishAsync(
    "telemetry/device-7",
    new TelemetryReading("device-7", 21.5),
    MqttQualityOfService.AtLeastOnce,
    cancellationToken: ct);

Consumers must use the same MessagePack contracts and resolver configuration for typed deserialization.

Failure behavior

• If no serializer is configured, typed APIs throw InvalidOperationException.
• Invalid MessagePack payloads are surfaced as MqttException.
• Resolver or contract mismatches fail during serialization/deserialization rather than being silently ignored.

Related docs

• Typed messaging
• Native AOT
• Serializer package overview