Transports

A transport is an adapter over one native client. Each transport package depends only on its native client and supports only that client's latest major version.

Package	Broker	Native client	Status
Relayer	In-memory, for tests and samples	Built in	Implemented
Relayer.Kafka	Apache Kafka	Dekaf, a pure C# Kafka client	In development
Relayer.AzureServiceBus	Azure Service Bus	Azure.Messaging.ServiceBus	In development
Relayer.AmazonSqs	Amazon SQS and SNS	AWSSDK.SQS and AWSSDK.SimpleNotificationService	In development
Relayer.RabbitMQ	RabbitMQ	RabbitMQ.Client	In development

Every transport, including third-party ones, must pass the transport conformance suite: send, receive, settle, retry, dead-letter, delay, ordering, trace propagation and reconnect.

Why Kafka uses Dekaf

Dekaf has no native dependencies, supports Native AOT and is built for zero-allocation hot paths, which matches Relayer's own goals. Where Dekaf already ships a feature, such as retry topics or OpenTelemetry instrumentation, the Kafka transport reuses it instead of re-implementing it.

Building a transport

The core is designed so a transport contains native code only. Start with:

• Writing a transport: registration, runtime adapters and the send seam.
• Receiving messages: the message binding and settlement.
• Consume pipeline: how a consumer is composed at startup.
• Envelopes and headers: mapping CloudEvents headers to native properties.
• Capabilities: what each endpoint declares.