Channels

channel models the transport path messages flow through (for example Kafka, MQTT, SQS, or HTTP streams).

Example

This example defines a Kafka channel and shows a service sending an event through that channel.

main.ec

channel OrdersChannel {
  version 1.0.0
  name "Orders Channel"
  summary "Carries order events"
  protocol "Kafka"
  address "orders.events.v1"
  owner platform-team
  route AnalyticsChannel@1.0.0
}

service OrdersService {
  version 1.0.0
  sends event OrderCreated@1.0.0 to OrdersChannel@1.0.0
}

Properties

Property	Type	Required	Description	Example
version	semver	Yes	Resource version.	1.0.0
name	string	No	Display name (defaults to id).	"Orders Channel"
summary	string	No	Short description.	"Carries order events"
owner	reference	No (repeatable)	Team/user owner reference.	owner platform-team
protocol	string	No	Transport technology/protocol.	"Kafka"
address	string	No	Broker/topic/queue address.	"orders.events.v1"
route	reference	No (repeatable)	Route from one channel to another.	route AnalyticsChannel@1.0.0
parameter	block	No (repeatable)	Dynamic address parameter.	parameter sensorId { ... }
draft	boolean	No	Marks resource as draft.	draft true
deprecated	boolean	No	Marks resource as deprecated.	deprecated true

Channel parameters

Use parameter to define dynamic segments in channel addresses:

main.ec

channel sensor-data {
  version 1.0.0
  address "sensors/{sensorId}/data"
  protocol "MQTT"

  parameter sensorId {
    description "Unique sensor identifier"
    default "sensor-001"
    enum ["sensor-001", "sensor-042", "sensor-099"]
    examples ["sensor-001", "sensor-042"]
  }
}

Parameter properties

Property	Type	Required	Description	Example
description	string	No	What the parameter represents	"Unique sensor identifier"
default	string	No	Default value	"sensor-001"
enum	string[]	No	Allowed values	["sensor-001", "sensor-042"]
examples	string[]	No	Example values	["sensor-001", "sensor-042"]

Channel routing

Channels can route to other channels, modeling message pipelines:

main.ec

channel Ingestion {
  version 1.0.0
  protocol "Kafka"
  route Filtered
  route Archive
}

channel Filtered {
  version 1.0.0
  protocol "Kafka"
  route Analytics
}

Used by services

Usage	Example
Send through a channel	sends event OrderCreated to OrdersChannel@1.0.0
Receive from a channel	receives event PaymentProcessed from PaymentsChannel@1.0.0