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Default Serialization

KafkaBus uses JSON serialization by default via System.Text.Json.

Default Behavior​

Producer​

Messages are serialized to JSON UTF-8 bytes:

// This message
var order = new OrderCreated(Guid.NewGuid(), "Product", 99.99m);
await messageBus.SendAsync("orders", order);

// Is serialized as
// {"Id":"...","ProductName":"Product","Amount":99.99}

Consumer​

Messages are deserialized from JSON UTF-8 bytes:

public override Task HandleAsync(
    ConsumeContext<string, OrderCreated> context,
    CancellationToken ct)
{
    // context.Message is already deserialized
    var order = context.Message;
    return Task.CompletedTask;
}

Default Serializers​

TypeSerializerDeserializer
Key (string)StringSerializer (Confluent)StringDeserializer (Confluent)
ValueDefaultSerializer<T> (JSON)DefaultDeserializer<T> (JSON)

JSON Options​

The default serializer uses standard System.Text.Json options:

public class DefaultSerializer<T> : ISerializer<T>
{
    public byte[] Serialize(T data, SerializationContext context)
    {
        return JsonSerializer.SerializeToUtf8Bytes(data);
    }
}

public class DefaultDeserializer<T> : IDeserializer<T>
{
    public T Deserialize(ReadOnlySpan<byte> data, bool isNull, SerializationContext context)
    {
        if (isNull || data.IsEmpty)
            return default!;
        return JsonSerializer.Deserialize<T>(data)!;
    }
}

Supported Types​

The default JSON serializer supports:

  • Records and classes
  • Primitive types
  • Collections (List, Array, Dictionary)
  • Nested objects
  • Nullable types
// All these work with default serialization
public record OrderCreated(Guid Id, string ProductName, decimal Amount);

public class Order
{
    public Guid Id { get; set; }
    public List<OrderItem> Items { get; set; }
    public Dictionary<string, string> Metadata { get; set; }
}

public record OrderItem(string ProductId, int Quantity, decimal? Discount);

Next Steps​