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: kinlane@gmail.com url: http://kinlane.com