Cumulocity · AsyncAPI Specification

Cumulocity MQTT Service

Version 2025.1

Standards-compliant, multi-tenant MQTT broker for application-level messaging that does not need Cumulocity's domain model. Topics are tenant-scoped, persistent, and bridgeable to the Cumulocity domain model via the Dynamic Mapper.

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Channels

{tenantId}/{topic}
publish publishGeneric
Publish to a tenant-scoped MQTT topic.
Tenant-scoped topic hierarchy for arbitrary application messages. Topics are isolated per tenant and persisted; subscribers receive missed messages on reconnect when using MQTT 5.0 session expiry.

Messages

✉
GenericMessage
Generic MQTT Message
Arbitrary application payload published on a tenant-scoped topic.

Servers

mqtts
production mqtt.{tenant}.cumulocity.com:8883
TLS-secured multi-tenant MQTT 5.0 broker.

AsyncAPI Specification

Raw ↑ 
asyncapi: 2.6.0
info:
  title: Cumulocity MQTT Service
  version: 2025.1
  description: |
    Standards-compliant, multi-tenant MQTT broker for application-level messaging that does not need
    Cumulocity's domain model. Topics are tenant-scoped, persistent, and bridgeable to the Cumulocity
    domain model via the Dynamic Mapper.
servers:
  production:
    url: 'mqtt.{tenant}.cumulocity.com:8883'
    protocol: mqtts
    description: TLS-secured multi-tenant MQTT 5.0 broker.
    variables:
      tenant:
        default: example
    security:
    - basicAuth: []
defaultContentType: application/json
channels:
  '{tenantId}/{topic}':
    description: Tenant-scoped topic hierarchy for arbitrary application messages. Topics are isolated per tenant
      and persisted; subscribers receive missed messages on reconnect when using MQTT 5.0 session expiry.
    parameters:
      tenantId:
        schema: {type: string}
      topic:
        schema: {type: string}
    publish:
      operationId: publishGeneric
      summary: Publish to a tenant-scoped MQTT topic.
      message:
        $ref: '#/components/messages/GenericMessage'
    subscribe:
      operationId: subscribeGeneric
      summary: Subscribe to a tenant-scoped MQTT topic.
      message:
        $ref: '#/components/messages/GenericMessage'
components:
  messages:
    GenericMessage:
      name: genericMessage
      title: Generic MQTT Message
      summary: Arbitrary application payload published on a tenant-scoped topic.
      payload:
        oneOf:
        - type: object
          additionalProperties: true
        - type: string
  securitySchemes:
    basicAuth:
      type: userPassword