AsyncAPI Initiative: Event-Driven API Specification

Visit asyncapi.com to learn about the initiative. Explore the Community section to understand the community behind AsyncAPI. Browse active projects on the GitHub organization at github.com/asyncapi. Tackle good first issues or resolve bugs via the Issues Dashboard at asyncapi.com/community/dashboard to build contributions for your proposal.

AsyncAPI is an Apache License 2.0 library under the Linux Foundation that provides specifications and open-source tools for event-driven architecture (EDA). It is similar to OpenAPI but for asynchronous APIs. The specification is platform and language agnostic, supporting common message brokers like Apache Kafka and RabbitMQ, and languages including Python, Java, and Node.js. The long-term goal is to make working with EDAs as easy as working with REST APIs, covering documentation, code generation, discovery, and event management.

Event-Driven Architecture (EDA) uses events to trigger and communicate between services, common in modern microservices applications. Unlike REST APIs where you make a request and wait for a response, EDA follows a 'fire and forget' pattern—useful when you only need confirmation that a message was received, not a direct response. Use EDA when communicating or informing that 'something happened' without requesting an action. Examples: user signups, new followers, sensor readings. Events communicate state changes or updates (e.g., adding an item to a cart).

The TSC is responsible for oversight of the AsyncAPI Initiative. Maintainers (committers) make decisions at the repository/project level, while the TSC handles higher-level decisions or when maintainers cannot reach consensus.

A producer is an application that detects state changes (events) and publishes these events as messages to a broker. In the publish/subscribe model, producers act as publishers and serve as the first logical layer for distributing messages to channels. An entity can simultaneously function as both a producer and a consumer by publishing to one channel while subscribing to another.

Renders an overview section for a WebSocket client, displaying the API description, version, and server URL. Accepts props: info (Info object from AsyncAPI document), title (string), and serverUrl (string). Returns a JSX.Element with a Text component containing the WebSocket client overview.

A template is a project that specifies the generation process output by using the AsyncAPI Generator and an AsyncAPI document. Template files describe the generation results depending on the AsyncAPI document's content. Templates can generate various outputs including code (Python, Java applications), documentation, Markdown diagrams, and HTML sites.

The AsyncAPI Maintainership Program is an 18-week annual mentorship initiative running from September to December. It equips contributors with source leadership skills and speaking opportunities at AsyncAPI global conferences. The program follows a structured timeline: announcement (early July), mentor/project selection (end of July), contributor applications (late July–early August), contribution period (mid–late August), mentee selection (late August–early September), official program kickoff (mid-September), midterm evaluations (October), final evaluations (December), and recognition (early January).

An Event-Driven Architecture (EDA) uses events to trigger and communicate between services, common in microservices. Unlike REST APIs where you make a request and wait for a response, EDAs follow a 'fire and forget' pattern—you communicate that 'something happened' without expecting a response. Events represent state changes or updates (e.g., adding an item to a cart). EDAs are typically broker-centric, with messages flowing through a message broker that stores and delivers them to interested subscribers.

Pavel Bodiachevskii has compiled AsyncAPI JVM tools under one website at asyncapi.pavelon.dev. The AsyncAPI Developer Network provides a centralized place to find information about the AsyncAPI specification and its JVM components. Users are encouraged to share feedback on the tools.

A publisher (producer) sends messages to the broker. A subscriber (consumer) connects to the broker, expresses interest in specific message types, and keeps the connection open so the broker can push matching messages to them. This decoupled pattern allows services to communicate without direct dependencies.