Events

name: Events
description: >-
  Event-driven APIs catalog. Documents the landscape of brokers, streaming
  platforms, schema registries, and the specifications that standardize how
  events are described, transported, and stored. "Events" is the broader
  category that contains webhooks (HTTP callbacks) as one delivery surface,
  alongside message brokers, log-based streaming platforms, and managed pub/sub
  services. The catalog aligns around CloudEvents (CNCF graduated, v1.0.2) as
  the spec for the event payload envelope and AsyncAPI as the spec for the
  event API surface (channels, operations, messages, servers), and covers the
  major open-source brokers (Apache Kafka, Apache Pulsar, NATS, Redpanda, IBM
  MQ), cloud-native managed buses (AWS EventBridge, Azure Event Grid, Google
  Cloud Pub/Sub, Confluent Cloud), schema registries (Confluent Schema
  Registry, Apicurio Registry), and streaming-analytics SaaS (Tinybird,
  Materialize). Wire-level protocols included are MQTT (OASIS), AMQP (OASIS /
  ISO 19464), and STOMP.
url: https://github.com/api-evangelist/events
humanURL: https://github.com/api-evangelist/events
image: ''
tags:
  - Events
  - Event-Driven
  - Event Streaming
  - Messaging
  - Pub Sub
  - Brokers
  - CloudEvents
  - AsyncAPI
  - Topic
created: '2026-05-22'
modified: '2026-05-22'
specificationVersion: '0.18'
type: Index

apis:
  - name: CloudEvents
    description: >-
      CNCF-graduated specification (graduated January 25, 2024) for describing
      event data in a common way. Defines a payload envelope with required
      attributes id, source, specversion, and type, and optional attributes
      datacontenttype, dataschema, subject, and time. Available format bindings
      cover JSON, AVRO, and Protobuf (XML and AVRO Compact in working draft);
      transport bindings cover HTTP, Kafka, AMQP, MQTT, NATS, and WebSockets.
      The CloudEvents 1.0.2 release is the current stable version, with 1.0.3
      in working draft.
    humanURL: https://cloudevents.io
    baseURL: ''
    tags:
      - Specification
      - Envelope
      - CNCF
      - Standards
    properties:
      - type: Portal
        url: https://cloudevents.io
      - type: Specification
        url: https://github.com/cloudevents/spec/blob/main/cloudevents/spec.md
      - type: GitHubOrganization
        url: https://github.com/cloudevents
      - type: GitHubRepository
        url: https://github.com/cloudevents/spec
      - type: SDK
        url: https://github.com/cloudevents/sdk-go
      - type: SDK
        url: https://github.com/cloudevents/sdk-javascript
      - type: SDK
        url: https://github.com/cloudevents/sdk-python
      - type: SDK
        url: https://github.com/cloudevents/sdk-java
      - type: SDK
        url: https://github.com/cloudevents/sdk-csharp
      - type: SDK
        url: https://github.com/cloudevents/sdk-rust

  - name: AsyncAPI
    description: >-
      Linux Foundation-hosted specification for event-driven APIs. Describes
      servers, channels, operations, messages, schemas, and protocol bindings
      for Kafka, AMQP, MQTT, NATS, WebSockets, HTTP, and more. AsyncAPI is the
      asynchronous counterpart to OpenAPI and provides a generator, CLI, and
      Studio for editing and validating documents.
    humanURL: https://www.asyncapi.com
    tags:
      - Specification
      - Async
      - Standards
      - Linux Foundation
    properties:
      - type: Portal
        url: https://www.asyncapi.com
      - type: Documentation
        url: https://www.asyncapi.com/docs
      - type: GitHubOrganization
        url: https://github.com/asyncapi
      - type: GitHubRepository
        url: https://github.com/asyncapi/spec
      - type: Tools
        url: https://studio.asyncapi.com
      - type: CLI
        url: https://github.com/asyncapi/cli

  - name: Apache Kafka
    description: >-
      Open-source distributed event streaming platform governed by the Apache
      Software Foundation. Described as used by "thousands of companies for
      high-performance data pipelines, streaming analytics, data integration,
      and mission-critical applications." Core abstractions: topics, partitions,
      offsets, producers, consumers, consumer groups, brokers. Kafka 4.x runs
      on KRaft (no ZooKeeper). Includes Kafka Streams (stream processing) and
      Kafka Connect (integration).
    humanURL: https://kafka.apache.org
    tags:
      - Broker
      - Streaming
      - Open Source
      - Apache
    properties:
      - type: Portal
        url: https://kafka.apache.org
      - type: Documentation
        url: https://kafka.apache.org/documentation
      - type: GitHubRepository
        url: https://github.com/apache/kafka
      - type: Protocol
        url: https://kafka.apache.org/protocol

  - name: Apache Pulsar
    description: >-
      Open-source distributed messaging and streaming platform built for the
      cloud. Top-10 Apache Software Foundation project (740+ contributors,
      current version 4.2). Multi-tenant by design (tenants, namespaces, topics,
      subscriptions), supports both queue and pub/sub messaging models, layered
      architecture separates stateless brokers from BookKeeper storage. Includes
      Pulsar Functions (serverless processing) and Pulsar IO (connectors).
    humanURL: https://pulsar.apache.org
    tags:
      - Broker
      - Streaming
      - Open Source
      - Apache
    properties:
      - type: Portal
        url: https://pulsar.apache.org
      - type: Documentation
        url: https://pulsar.apache.org/docs
      - type: GitHubRepository
        url: https://github.com/apache/pulsar

  - name: NATS
    description: >-
      CNCF incubating high-performance, lightweight messaging system designed
      for cloud, edge, and IoT. Supports pub/sub, request/reply, and queue
      groups over a text-based protocol. JetStream extends NATS with persistent
      streams, key-value, and object storage. Official clients in Go, Rust,
      JavaScript/TypeScript, Python, Java, C#, C, Ruby, and Elixir.
    humanURL: https://nats.io
    tags:
      - Broker
      - Messaging
      - CNCF
      - Open Source
    properties:
      - type: Portal
        url: https://nats.io
      - type: Documentation
        url: https://docs.nats.io
      - type: GitHubOrganization
        url: https://github.com/nats-io
      - type: GitHubRepository
        url: https://github.com/nats-io/nats-server

  - name: Redpanda
    description: >-
      Kafka API-compatible streaming data platform written in C++ (no JVM, no
      ZooKeeper). Self-described as an "Agentic Data Plane and Data Streaming
      platform for real-time performance, AI innovation, and simplified
      operations." Ships Redpanda Connect (integration), Redpanda SQL (query
      engine, post Oxla acquisition), and Redpanda Cloud (managed SaaS).
      Source-available under the Business Source License.
    humanURL: https://redpanda.com
    tags:
      - Broker
      - Streaming
      - Kafka API
      - Hosted
    properties:
      - type: Portal
        url: https://redpanda.com
      - type: Documentation
        url: https://docs.redpanda.com
      - type: GitHubOrganization
        url: https://github.com/redpanda-data
      - type: GitHubRepository
        url: https://github.com/redpanda-data/redpanda

  - name: IBM MQ
    description: >-
      Enterprise messaging middleware from IBM. Long the de facto standard for
      assured-once message delivery in regulated industries (banking,
      government). Exposes the MQI native API, JMS, AMQP 1.0, MQTT, and a REST
      messaging API. Current generation is IBM MQ 9.4.
    humanURL: https://www.ibm.com/products/mq
    tags:
      - Broker
      - Messaging
      - Enterprise
    properties:
      - type: Portal
        url: https://www.ibm.com/products/mq
      - type: Documentation
        url: https://www.ibm.com/docs/en/ibm-mq

  - name: AWS EventBridge
    description: >-
      AWS serverless event router. "EventBridge is a serverless service that
      uses events to connect application components together, making it easier
      for you to build scalable event-driven applications." Two delivery
      surfaces: event buses (many-to-many routing) and pipes (point-to-point
      with optional enrichment/transform). EventBridge Scheduler adds cron/rate
      scheduling. Includes a Schema Registry that supports JSON Schema and
      OpenAPI 3 representations of EventBridge events.
    humanURL: https://aws.amazon.com/eventbridge
    tags:
      - Bus
      - Cloud
      - AWS
      - Serverless
    properties:
      - type: Portal
        url: https://aws.amazon.com/eventbridge
      - type: Documentation
        url: https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-what-is.html
      - type: APIReference
        url: https://docs.aws.amazon.com/eventbridge/latest/APIReference

  - name: Azure Event Grid
    description: >-
      Azure's "highly scalable and fully managed publish-subscribe service for
      message distribution." Supports both HTTP push/pull delivery and an MQTT
      v3.1.1 / v5.0 broker mode for IoT clients. Supports CloudEvents 1.0
      natively and the Event Grid native schema. Concepts include namespaces,
      topics (system, custom, partner, domain), event subscriptions, and dead
      lettering.
    humanURL: https://azure.microsoft.com/en-us/products/event-grid
    tags:
      - Bus
      - Cloud
      - Azure
      - MQTT
    properties:
      - type: Portal
        url: https://azure.microsoft.com/en-us/products/event-grid
      - type: Documentation
        url: https://learn.microsoft.com/en-us/azure/event-grid/overview

  - name: Google Cloud Pub/Sub
    description: >-
      Google Cloud's asynchronous and scalable messaging service that decouples
      message producers from consumers with typical latencies around 100 ms.
      Uses per-message leasing (not partitions) for parallel processing. Topics
      and subscriptions (push and pull), schemas (Avro and Protobuf), ordering
      keys, dead-letter topics, snapshots, and seek. Pub/Sub Lite offers a
      cheaper zonal/regional partitioned variant for high-volume workloads.
    humanURL: https://cloud.google.com/pubsub
    tags:
      - Bus
      - Cloud
      - Google Cloud
      - Managed
    properties:
      - type: Portal
        url: https://cloud.google.com/pubsub
      - type: Documentation
        url: https://cloud.google.com/pubsub/docs/overview
      - type: APIReference
        url: https://cloud.google.com/pubsub/docs/reference/rest

  - name: Confluent Cloud
    description: >-
      Commercial managed service from Confluent positioned as "the industry's
      only fully managed data streaming platform." Built on the Kora
      cloud-native Kafka engine. Tiers: Basic, Standard, Enterprise, and
      Freight. Bundles Kafka, Schema Registry, Connect (120+ pre-built
      connectors, 90+ fully managed), Stream Governance, Tableflow (topics to
      tables), and Confluent Cloud for Apache Flink for stream processing.
      99.99% uptime SLA on multi-AZ deployments. Runs on AWS, Azure, and GCP.
    humanURL: https://www.confluent.io/confluent-cloud
    tags:
      - Streaming
      - Hosted
      - Kafka
      - SaaS
    properties:
      - type: Portal
        url: https://www.confluent.io/confluent-cloud
      - type: Documentation
        url: https://docs.confluent.io/cloud/current/overview.html
      - type: APIReference
        url: https://docs.confluent.io/cloud/current/api.html
      - type: Pricing
        url: https://www.confluent.io/confluent-cloud/pricing

  - name: Confluent Schema Registry
    description: >-
      Central repository with a RESTful interface for registering and evolving
      schemas in Avro, JSON Schema, and Protobuf. Enforces compatibility rules
      (backward, forward, full, transitive) for Kafka topics. Available in
      Confluent Platform and as a managed component of Confluent Cloud. Schema
      Linking syncs schemas across hybrid and multicloud deployments.
    humanURL: https://docs.confluent.io/platform/current/schema-registry/index.html
    tags:
      - Registry
      - Schemas
      - Governance
    properties:
      - type: Documentation
        url: https://docs.confluent.io/platform/current/schema-registry/index.html
      - type: APIReference
        url: https://docs.confluent.io/platform/current/schema-registry/develop/api.html
      - type: GitHubRepository
        url: https://github.com/confluentinc/schema-registry

  - name: Apicurio Registry
    description: >-
      Open-source schema and API artifact registry backed by Red Hat (Apache
      2.0). Stores OpenAPI, AsyncAPI, Avro, JSON Schema, Protobuf, Kafka
      Connect schemas, GraphQL SDL, WSDL, and XSD. Configurable content rules
      drive evolution and validity checks; storage backends include Kafka,
      PostgreSQL, and Microsoft SQL Server. Latest stable version 3.2.4.
    humanURL: https://www.apicur.io/registry
    tags:
      - Registry
      - Schemas
      - Open Source
      - Red Hat
    properties:
      - type: Portal
        url: https://www.apicur.io/registry
      - type: Documentation
        url: https://www.apicur.io/registry/docs
      - type: GitHubRepository
        url: https://github.com/Apicurio/apicurio-registry

  - name: Tinybird
    description: >-
      Managed ClickHouse-based SaaS for real-time analytics on event data.
      Ingests events via an HTTP Events API (up to 1,000 req/s) plus connectors
      for Kafka, S3, GCS, BigQuery, Snowflake, and PostgreSQL. Pipes transform
      streaming data; published APIs expose SQL queries as HTTP endpoints with
      sub-second latency. Customer footprint cited: 1.47B requests/month.
    humanURL: https://www.tinybird.co
    tags:
      - Streaming
      - Analytics
      - SaaS
      - ClickHouse
    properties:
      - type: Portal
        url: https://www.tinybird.co
      - type: Documentation
        url: https://www.tinybird.co/docs
      - type: APIReference
        url: https://www.tinybird.co/docs/get-data-in/ingest-apis/events-api

  - name: Materialize
    description: >-
      Streaming SQL database based on incremental view maintenance. Continually
      ingests CDC from Postgres, Kafka, and other sources, then keeps SQL views
      up to date with minimal recomputation. Materialized views act as
      continuously-updated event streams that downstream apps subscribe to.
      Available as managed cloud, self-managed, and a local emulator.
    humanURL: https://materialize.com
    tags:
      - Streaming
      - SQL
      - CDC
      - SaaS
    properties:
      - type: Portal
        url: https://materialize.com
      - type: Documentation
        url: https://materialize.com/docs

  - name: MQTT
    description: >-
      OASIS standard messaging protocol for the Internet of Things. Lightweight
      publish/subscribe transport for remote, constrained devices. Current
      version is MQTT 5.0 (predecessors 3.1, 3.1.1). Three QoS levels (0 at
      most once, 1 at least once, 2 exactly once), retained messages,
      last-will, persistent sessions, MQTT over WebSockets, TLS, and OAuth /
      JWT authentication. MQTT-SN targets very constrained networks.
    humanURL: https://mqtt.org
    tags:
      - Protocol
      - IoT
      - Pub Sub
      - OASIS
    properties:
      - type: Portal
        url: https://mqtt.org
      - type: Specification
        url: https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.html

  - name: AMQP
    description: >-
      Advanced Message Queuing Protocol. AMQP 1.0 is both an OASIS standard
      and an International Standard (ISO/IEC 19464). Wire-level binary protocol
      defining nodes, links, sessions, and frames. Mission per the spec home:
      "To become the standard protocol for interoperability between all
      messaging middleware." Major implementations include Microsoft Azure
      Service Bus, Apache ActiveMQ Artemis, and SwiftMQ for 1.0; RabbitMQ
      remains the canonical AMQP 0-9-1 implementation.
    humanURL: https://www.amqp.org
    tags:
      - Protocol
      - Messaging
      - OASIS
      - ISO
    properties:
      - type: Portal
        url: https://www.amqp.org
      - type: Specification
        url: http://docs.oasis-open.org/amqp/core/v1.0/os/amqp-core-overview-v1.0-os.html

  - name: STOMP
    description: >-
      Simple (or Streaming) Text Oriented Messaging Protocol. Lightweight,
      text-based wire protocol for message-oriented middleware. Widely used as
      an alternative front-end on brokers like Apache ActiveMQ, RabbitMQ, and
      HornetQ, especially from browser JavaScript clients via WebSocket.
    humanURL: https://stomp.github.io
    tags:
      - Protocol
      - Messaging
      - Text Based
    properties:
      - type: Portal
        url: https://stomp.github.io
      - type: Specification
        url: https://stomp.github.io/stomp-specification-1.2.html

common:
  - type: Portal
    url: https://github.com/api-evangelist/events
  - type: GitHubOrganization
    url: https://github.com/api-evangelist
  - type: Vocabulary
    url: vocabulary/events-vocabulary.yml
  - type: JSONLD
    url: json-ld/events-context.jsonld

  - type: Features
    data:
      - name: Pub Sub Messaging
        description: >-
          Many-to-many fan-out where producers publish to a topic and any
          number of subscribers receive a copy. Core to MQTT, NATS, Google
          Pub/Sub, Kafka (consumer-group fan-out), and EventBridge.
      - name: Queue Messaging
        description: >-
          Point-to-point work distribution where each message is consumed by
          exactly one worker. Native to IBM MQ, RabbitMQ (AMQP 0-9-1), Pulsar
          shared subscriptions, and NATS queue groups.
      - name: Log Based Streaming
        description: >-
          Durable, ordered, partitioned commit log that consumers read by
          offset. Kafka and Redpanda are the canonical implementations; Pulsar
          and Pub/Sub Lite share many properties.
      - name: Schema Governance
        description: >-
          Schema registries (Confluent, Apicurio) version event schemas and
          enforce compatibility rules so producers cannot break consumers.
      - name: CloudEvents Envelope
        description: >-
          Standard required attributes (id, source, specversion, type) plus
          optional (datacontenttype, dataschema, subject, time) wrap any event
          payload, with bindings for HTTP, Kafka, AMQP, MQTT, NATS,
          WebSockets, JSON, Avro, and Protobuf.
      - name: AsyncAPI Description
        description: >-
          AsyncAPI documents describe the channels, operations, messages, and
          bindings of an event-driven API the way OpenAPI describes a REST
          API.

  - type: UseCases
    data:
      - name: Microservice Integration
        description: >-
          Decoupling services so producers emit events without coupling to
          downstream consumers.
      - name: Change Data Capture
        description: >-
          Replicating database changes (Postgres logical replication, MySQL
          binlog, MongoDB change streams) onto Kafka, Pulsar, or Materialize
          for downstream consumers.
      - name: IoT Telemetry
        description: >-
          Constrained devices publishing readings over MQTT or NATS to cloud
          gateways such as Azure Event Grid or AWS IoT Core.
      - name: Real Time Analytics
        description: >-
          Streaming events into ClickHouse-, Pinot-, or Druid-based platforms
          (Tinybird, Materialize) to power user-facing dashboards with
          sub-second freshness.
      - name: Event Sourcing
        description: >-
          Storing every state change as an immutable event in a durable log
          (Kafka, Pulsar) so application state can be rebuilt by replay.
      - name: Webhook Delivery
        description: >-
          HTTP-based fan-out from a SaaS to subscriber URLs. The narrowest
          slice of the event landscape; covered in detail in the api-evangelist
          webhooks topic repo.

  - type: Integrations
    data:
      - name: CloudEvents
        description: >-
          Common envelope adopted across Azure Event Grid, Knative, GitHub
          Webhooks (via cloudevents-go binding), and most CNCF event-emitting
          projects.
      - name: AsyncAPI
        description: >-
          API description format used by Postman, Microcks, Apicurio, and
          numerous broker dashboards to render an event API surface.
      - name: Kafka Protocol
        description: >-
          De facto wire protocol; supported natively by Confluent Cloud,
          Redpanda, Aiven, and (via proxies) Azure Event Hubs and Pulsar.
      - name: MQTT
        description: >-
          Native protocol for Azure Event Grid namespaces, AWS IoT Core, HiveMQ,
          EMQX, and Mosquitto.
      - name: Schema Registry
        description: >-
          Confluent Schema Registry and Apicurio Registry plug into Kafka
          serializers/deserializers in every major language client.

  - type: Solutions
    data:
      - name: Open Source Brokers
        description: >-
          Apache Kafka, Apache Pulsar, NATS, Redpanda Community Edition, and
          RabbitMQ cover most self-hosted deployments.
      - name: Managed Cloud Buses
        description: >-
          AWS EventBridge, Azure Event Grid, and Google Cloud Pub/Sub provide
          serverless, pay-per-event delivery within their respective clouds.
      - name: Managed Streaming SaaS
        description: >-
          Confluent Cloud, Redpanda Cloud, Aiven for Kafka, and Tinybird offer
          fully managed Kafka or ClickHouse with their own consoles, APIs, and
          SLAs.
      - name: Specification Stack
        description: >-
          CloudEvents (envelope), AsyncAPI (API description), and JSON Schema
          / Avro / Protobuf (payload schema) compose into the standards layer
          that brokers and registries implement.

  - type: RelatedTopics
    data:
      - name: Webhooks
        description: >-
          HTTP callbacks are the narrowest delivery surface of the event
          landscape. See the api-evangelist webhooks topic repo for the
          dedicated index.
      - name: Streaming
        description: >-
          Log-based event streaming overlaps heavily with Kafka and Pulsar.
      - name: Async APIs
        description: >-
          AsyncAPI-specific tooling and ecosystem.
      - name: Event Driven Architecture
        description: >-
          Architectural patterns built on top of these brokers and specs.
      - name: Event Sourcing
        description: >-
          A specific pattern using durable event logs as the system of record.

maintainers:
  - FN: Kin Lane
    email: [email protected]
    url: http://kinlane.com