AsyncAPI Specification
If you have event-driven systems (Kafka, RabbitMQ, WebSocket APIs, IoT), AsyncAPI is the description format. Analogous to OpenAPI for async what OpenAPI is for REST.
What It Defines
OpenAPI-equivalent for event-driven APIs. Describes channels, messages, bindings (WebSocket, MQTT, Kafka, AMQP, etc.), and schemas for async/event-based systems. Enables documentation and code generation for message-based architectures.
Canonical (Normative)
Convenient (Practical)
Maintains the AsyncAPI specification — an OpenAPI-like description language for event-driven and message-based APIs. Covers WebSocket, MQTT, AMQP, Kafka, and more.
Related Specs
OpenAPI is the de-facto standard for API documentation, code generation, mock servers, and contract testing. Most APIs you build should have an OpenAPI spec.
Real-time features — chat, live dashboards, collaborative editing, notifications, trading UIs — run on WebSockets. Every serious app eventually needs them.
JSON Schema is the standard way to document and validate API request/response shapes. OpenAPI 3.1 fully adopts it. Know it if you design APIs.