Asynchronous plane and brokers

Product guide: what the capability brings, for whom, its limits and the version that delivered it - no configuration syntax.

What it does	Puts a message broker behind the same controls as HTTP, in both directions, under an AsyncAPI contract. An HTTP service or an agent tool publishes without embedding a broker client (202 once the message is acknowledged); a browser or an application subscribes over SSE or WebSocket (at least once); a partner receives signed webhooks (Standard Webhooks), with retries and a dead-letter channel
Why it matters	Each subscriber reads its tenant only, or even its own messages only. Messages carry a standard envelope (CloudEvents) and the trace. No more exposing a broker to the Internet or handing out its credentials
Brokers	Kafka, RabbitMQ (AMQP 0-9-1), MQTT 5 and 3.1.1 (1.5.0); NATS Core and JetStream, AMQP 1.0 - RabbitMQ 4, Azure Service Bus, ActiveMQ Artemis, Solace (1.6.0)
Binary payloads	Avro, Protobuf and CBOR under schema, validated when the operation asks, turned into JSON toward SSE and webhooks; a read-only schema registry (Confluent API) (1.6.0)
Use cases	Notify a customer's screen of its order's events live; deliver invoices to a partner by signed webhook; publish from a service with no Kafka dependency; broadcast a public feed to anonymous visitors
Limits	The gateway creates no topic or queue; it is a broker client, not a broker; MQTT devices connecting to the gateway (IoT, Sparkplug B, OPC UA) come in 1.7.0
Since	1.5.0; 1.6.0 for NATS, AMQP 1.0 and binary payloads
Configure	Publishing and consuming on a broker