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

  - url: graphql/events-graphql.md
    type: GraphQL
- 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: kinlane@gmail.com
  url: http://kinlane.com