Async Event API Documentation

Document event-driven and asynchronous APIs with channels, operations, messages, protocol bindings across a wide range of protocols, security schemes, reusable traits, and AsyncAPI 3.0 export in NeoArc Studio.

February 25, 2026

The async API editor documents event-driven and asynchronous APIs alongside your REST and GraphQL documentation. Define message brokers, channels, operations, messages, and protocol-specific bindings in a structured format that follows the AsyncAPI 3.0 specification and publishes as a browsable async API reference on your documentation site.

Core Concepts

Async API documentation is organised around four resource types that mirror the AsyncAPI 3.0 specification:

Channels

Topics, queues, and subjects where messages are exchanged. Define addresses with dynamic parameters, link to available messages, and configure protocol-specific bindings like Kafka partitions and retention policies.

Operations

Send (publish) or receive (subscribe) actions from your application's perspective. Each operation links to a channel and its messages, with optional request-reply configuration and per-operation security overrides.

Messages

The data structures exchanged through channels. Each message references a payload schema and optional headers schema, with correlation IDs for distributed tracing and concrete JSON examples.

Servers

Broker configurations with protocol selection, host addresses, and server-level bindings. Support multiple environments (production, staging, development) with protocol-specific settings.

Protocol Support

A wide range of protocols across six categories, including MQTT, AMQP, Kafka, WebSocket and others:

Streaming

Apache Kafka with Schema Registry integration, and Apache Pulsar with tenant/namespace support.

Messaging

AMQP 0-9-1, AMQP 1.0, NATS, JMS, STOMP, and Redis Pub/Sub with exchange, queue, and routing bindings.

Web and IoT

HTTP, WebSocket, Mercure for web protocols. MQTT and MQTT 5.0 with QoS levels for IoT scenarios.

Cloud and Enterprise

Amazon SNS, Amazon SQS, Google Pub/Sub for cloud messaging. IBM MQ and Solace PubSub+ for enterprise integration.

Security

A comprehensive set of security scheme types designed for broker and event-driven authentication:

SASL Authentication

PLAIN, SCRAM-SHA-256, SCRAM-SHA-512, and GSSAPI (Kerberos) for Kafka and enterprise broker authentication.

OAuth2 and OpenID Connect

Token-based authentication with four grant flows and scope-based access control for topics and Schema Registry.

Certificates and Encryption

X.509 for mTLS connections. Symmetric and asymmetric encryption for message-level security.

Keys and Passwords

HTTP Bearer/Basic/Digest, API keys (header/query/cookie), and broker-native user/password authentication.

Reusable Traits

Define cross-cutting properties once and apply them to multiple messages or operations:

Message Traits

Shared headers schemas, correlation ID patterns, content type defaults, and protocol bindings. Apply a CorrelatedMessage trait so that every event carries tracing headers.

Operation Traits

Shared security requirements, protocol bindings, and tags. Apply an AuthenticatedOperation trait to enforce consistent authentication across all operations.

Supported Protocols

Each protocol has dedicated binding configuration in both the editor and the published viewer.

Category	Protocols	Key Bindings
Streaming	Apache Kafka, Apache Pulsar	Schema Registry, partitions, retention, consumer groups, tenant/namespace
Messaging	AMQP 0-9-1, AMQP 1.0, NATS, JMS, STOMP, Redis Pub/Sub	Exchanges, queues, routing keys, durable subscribers, message selectors
Web	HTTP, WebSocket, Mercure	Methods, headers, connection upgrade, hub URLs, topic selectors
IoT	MQTT, MQTT 5.0	QoS levels (0/1/2), retain, will messages, session expiry, topic aliases
Cloud	Amazon SNS, Amazon SQS, Google Pub/Sub	Topics, subscriptions, dead-letter queues, message filtering, ordering keys
Enterprise	IBM MQ, Solace PubSub+	Queue managers, channels, message persistence, VPN configuration

Schema Integration

Viewer

The published site includes an async API browser that presents all documented event-driven APIs.

Navigation Panel

Browse channels (with address display), operations (with send/receive badges), messages, and API info. Active selection highlighting and auto-expansion.

Searchable

Async API definitions are included in the published site search index. Find channels, operations, and messages by name, address, or description.

Version Controlled

Async API definitions are JSON files stored in your Git repository. Track changes, review in pull requests, and roll back when needed.

AsyncAPI 3.0 Export

Export your async API documentation to the standard AsyncAPI 3.0 format for use with other tools in the AsyncAPI ecosystem. Import existing AsyncAPI specifications to get started quickly.

Use Cases

Service Integration Docs

Document which services publish and subscribe to which events, with authentication requirements and payload schemas for each integration point.

Consumer Developer Reference

Provide concrete message examples with headers and payloads so consuming teams have copy-paste-ready test data.

Event Governance

Track event schemas, deprecations, and security requirements to maintain event contract quality and enforce organisational standards.

API Documentation

Document REST APIs with full endpoint specifications, OpenAPI import and export, seven HTTP methods, parameters, request and response bodies linked to shared schemas, authentication schemes, and a published API browser. REST is part of the API documentation suite (REST, GraphQL, gRPC, AsyncAPI, Webhooks, MCP) sharing a unified schema layer.

GraphQL API Documentation

Document GraphQL APIs with queries, mutations, subscriptions, custom scalars, directives, interfaces, and per-operation authentication in NeoArc Studio.

Webhook API Documentation

Document webhook-based integrations with event definitions, HMAC signature verification, delivery guarantees, retry policies, dead letter queues, circuit breakers, and consumer guidance. The structured webhook editor captures what architects need to express about push-based event notifications.

Schema Editor

Define data structures with field types covering strings, numbers, booleans, objects, arrays and more, type specialisations for fine-grained modelling, and validation rules covering type safety, cardinality, referential integrity and cross-field constraints. Create reusable schemas that stay synchronised across your documentation.