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: SDKs
    url: https://github.com/cloudevents/sdk-go
  - type: SDKs
    url: https://github.com/cloudevents/sdk-javascript
  - type: SDKs
    url: https://github.com/cloudevents/sdk-python
  - type: SDKs
    url: https://github.com/cloudevents/sdk-java
  - type: SDKs
    url: https://github.com/cloudevents/sdk-csharp
  - type: SDKs
    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