Quarkus Messaging — SmallRye Reactive Messaging

Overview

Expert guidance for event-driven architectures in Quarkus 3.36.0 using SmallRye Reactive Messaging. Supports Kafka, RabbitMQ, AMQP 1.0, MQTT, and in-memory channels with a unified @Incoming / @Outgoing programming model.

Key Capabilities:

• @Incoming / @Outgoing annotations for declarative message wiring
• Emitter<T> / @Channel for programmatic publishing
• Multi<T> and Uni<T> return types for reactive pipelines
• @Blocking for blocking consumer methods
• Kafka connector: topics, consumer groups, partitions, offsets, serialization
• RabbitMQ connector: exchanges, queues, routing keys
• AMQP 1.0 connector: queues, addresses
• Dead Letter Queue, @Retry, manual nack, exactly-once with KafkaTransactions
• Acknowledgment strategies: POST_PROCESSING, PRE_PROCESSING, MANUAL, NONE
• Kafka Dev Services (Redpanda container, auto-topic creation)
• Micrometer metrics + OpenTelemetry tracing