Scalable Architecture · Schema

Domain Event

Describes a domain event in an event-driven scalable architecture, following CloudEvents conventions. Domain events enable loose coupling between microservices through async message passing over Kafka, RabbitMQ, or cloud message brokers.

Cloud ArchitectureCloud NativeDistributed SystemsHigh AvailabilityInfrastructureMicroservicesPerformanceResilienceScalabilityService Mesh

Properties

Name	Type	Description
specversion	string	CloudEvents specification version.
id	string	Unique identifier for this event occurrence.
source	string	URI identifying the context in which the event occurred (typically the originating service).
type	string	Event type in reverse-DNS notation describing the kind of occurrence.
subject	string	Identifies the subject of the event in the context of the source (e.g., entity ID).
datacontenttype	string	Content type of the event data.
dataschema	string	URI identifying the schema for the event data payload.
time	string	Timestamp of when the event occurred in RFC3339 format.
data	object	Domain event payload specific to the event type.
partitionkey	string	Key used to route the event to a specific Kafka partition for ordering guarantees.
correlationid	string	Correlation ID for tracing a business transaction across multiple services.
causationid	string	ID of the command or event that caused this event (event sourcing lineage).
metadata	object	Additional metadata properties for routing, filtering, and tracing.

View JSON Schema on GitHub

JSON Schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/api-evangelist/scalable-architecture/main/json-schema/scalable-architecture-event-schema.json",
  "title": "Domain Event",
  "description": "Describes a domain event in an event-driven scalable architecture, following CloudEvents conventions. Domain events enable loose coupling between microservices through async message passing over Kafka, RabbitMQ, or cloud message brokers.",
  "type": "object",
  "required": ["id", "source", "specversion", "type"],
  "properties": {
    "specversion": {
      "type": "string",
      "description": "CloudEvents specification version.",
      "const": "1.0"
    },
    "id": {
      "type": "string",
      "description": "Unique identifier for this event occurrence.",
      "format": "uuid",
      "example": "96fb5f0b-001e-0108-6d02-a85e0000000"
    },
    "source": {
      "type": "string",
      "description": "URI identifying the context in which the event occurred (typically the originating service).",
      "format": "uri",
      "example": "/orders/service"
    },
    "type": {
      "type": "string",
      "description": "Event type in reverse-DNS notation describing the kind of occurrence.",
      "pattern": "^[a-z][a-z0-9.]+$",
      "examples": [
        "com.example.orders.created",
        "com.example.payments.completed",
        "com.example.inventory.updated"
      ]
    },
    "subject": {
      "type": "string",
      "description": "Identifies the subject of the event in the context of the source (e.g., entity ID).",
      "example": "order-12345"
    },
    "datacontenttype": {
      "type": "string",
      "description": "Content type of the event data.",
      "default": "application/json",
      "examples": ["application/json", "application/avro"]
    },
    "dataschema": {
      "type": "string",
      "description": "URI identifying the schema for the event data payload.",
      "format": "uri"
    },
    "time": {
      "type": "string",
      "description": "Timestamp of when the event occurred in RFC3339 format.",
      "format": "date-time",
      "example": "2026-05-02T14:30:00Z"
    },
    "data": {
      "type": "object",
      "description": "Domain event payload specific to the event type.",
      "additionalProperties": true
    },
    "partitionkey": {
      "type": "string",
      "description": "Key used to route the event to a specific Kafka partition for ordering guarantees.",
      "example": "customer-456"
    },
    "correlationid": {
      "type": "string",
      "description": "Correlation ID for tracing a business transaction across multiple services.",
      "format": "uuid"
    },
    "causationid": {
      "type": "string",
      "description": "ID of the command or event that caused this event (event sourcing lineage).",
      "format": "uuid"
    },
    "metadata": {
      "type": "object",
      "description": "Additional metadata properties for routing, filtering, and tracing.",
      "properties": {
        "retryCount": {
          "type": "integer",
          "description": "Number of times this event has been retried.",
          "minimum": 0,
          "default": 0
        },
        "deadLetterQueue": {
          "type": "boolean",
          "description": "Whether this event has been moved to the dead letter queue.",
          "default": false
        },
        "version": {
          "type": "integer",
          "description": "Schema version for event evolution.",
          "minimum": 1,
          "default": 1
        }
      }
    }
  }
}