Domain Event

Schema for a domain event in an event-sourced or event-driven system following CloudEvents conventions.

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Properties

Name	Type	Description
specversion	string	CloudEvents specification version.
type	string	Event type in reverse DNS notation.
source	string	Identifies the event producer (bounded context or service).
id	string	Unique identifier for this event occurrence (UUID recommended).
time	string	Timestamp when the event occurred (RFC 3339).
subject	string	Subject/entity identifier this event relates to (e.g., order ID).
datacontenttype	string	Content type of the data field.
dataschema	string	URI of the schema the data attribute conforms to.
data	object	Event payload. Schema depends on event type.
correlationId	string	Correlation ID for tracing requests across service boundaries.
causationId	string	ID of the command or event that caused this event.
aggregateId	string	Identifier of the domain aggregate this event belongs to.
aggregateType	string	Type of the domain aggregate (e.g., Order, Customer, Payment).
aggregateVersion	integer	Optimistic concurrency version of the aggregate after this event.
metadata	object	Additional metadata (user ID, tenant ID, trace context, etc.).

View JSON Schema on GitHub

JSON Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://api-evangelist.com/schemas/scalable-software-and-systems/domain-event",
  "title": "Domain Event",
  "description": "Schema for a domain event in an event-sourced or event-driven system following CloudEvents conventions.",
  "type": "object",
  "required": ["specversion", "type", "source", "id", "time"],
  "properties": {
    "specversion": {
      "type": "string",
      "description": "CloudEvents specification version.",
      "enum": ["1.0"],
      "example": "1.0"
    },
    "type": {
      "type": "string",
      "description": "Event type in reverse DNS notation.",
      "example": "com.example.order.placed"
    },
    "source": {
      "type": "string",
      "format": "uri-reference",
      "description": "Identifies the event producer (bounded context or service).",
      "example": "/orders-service"
    },
    "id": {
      "type": "string",
      "description": "Unique identifier for this event occurrence (UUID recommended).",
      "example": "b2c3d4e5-f6a7-8901-bcde-f01234567890"
    },
    "time": {
      "type": "string",
      "format": "date-time",
      "description": "Timestamp when the event occurred (RFC 3339)."
    },
    "subject": {
      "type": "string",
      "description": "Subject/entity identifier this event relates to (e.g., order ID).",
      "example": "order-12345"
    },
    "datacontenttype": {
      "type": "string",
      "description": "Content type of the data field.",
      "default": "application/json",
      "example": "application/json"
    },
    "dataschema": {
      "type": "string",
      "format": "uri",
      "description": "URI of the schema the data attribute conforms to."
    },
    "data": {
      "type": "object",
      "description": "Event payload. Schema depends on event type.",
      "additionalProperties": true
    },
    "correlationId": {
      "type": "string",
      "description": "Correlation ID for tracing requests across service boundaries."
    },
    "causationId": {
      "type": "string",
      "description": "ID of the command or event that caused this event."
    },
    "aggregateId": {
      "type": "string",
      "description": "Identifier of the domain aggregate this event belongs to."
    },
    "aggregateType": {
      "type": "string",
      "description": "Type of the domain aggregate (e.g., Order, Customer, Payment)."
    },
    "aggregateVersion": {
      "type": "integer",
      "minimum": 0,
      "description": "Optimistic concurrency version of the aggregate after this event."
    },
    "metadata": {
      "type": "object",
      "description": "Additional metadata (user ID, tenant ID, trace context, etc.).",
      "properties": {
        "userId": { "type": "string" },
        "tenantId": { "type": "string" },
        "traceId": { "type": "string" },
        "spanId": { "type": "string" }
      },
      "additionalProperties": true
    }
  }
}