ThingSpeak MQTT API

asyncapi: 2.6.0
info:
  title: ThingSpeak MQTT API
  version: '1.0'
  description: |
    ThingSpeak's MQTT broker at `mqtt3.thingspeak.com`. Devices publish channel
    updates and subscribe to channel/field feeds using MQTT credentials (Client ID,
    Username, Password) provisioned in the ThingSpeak portal.

    Available transports:
    - TCP on port 1883 (unencrypted)
    - TCP on port 8883 (TLS)
    - WebSocket on port 80 (path `/mqtt`, unencrypted)
    - WebSocket on port 443 (path `/mqtt`, TLS)

    QoS 0 only. Connections time out after one hour of inactivity.
servers:
  production-tcp:
    url: mqtt3.thingspeak.com:1883
    protocol: mqtt
    description: Production MQTT broker (unencrypted TCP).
  production-tcp-tls:
    url: mqtt3.thingspeak.com:8883
    protocol: mqtts
    description: Production MQTT broker (TLS TCP).
  production-ws:
    url: mqtt3.thingspeak.com:80/mqtt
    protocol: ws
    description: Production MQTT broker (unencrypted WebSocket).
  production-wss:
    url: mqtt3.thingspeak.com:443/mqtt
    protocol: wss
    description: Production MQTT broker (TLS WebSocket).
channels:
  channels/{channelID}/publish:
    description: Publish multi-field updates to a channel. Payload is form-encoded
      (`field1=value&field2=value&status=...`).
    parameters:
      channelID:
        schema:
          type: integer
    publish:
      operationId: publishChannelFeed
      message:
        $ref: '#/components/messages/ChannelUpdate'
  channels/{channelID}/publish/fields/field{fieldNumber}:
    description: Publish a single field's value.
    parameters:
      channelID:
        schema:
          type: integer
      fieldNumber:
        schema:
          type: integer
          minimum: 1
          maximum: 8
    publish:
      operationId: publishFieldValue
      message:
        $ref: '#/components/messages/FieldValue'
  channels/{channelID}/subscribe/fields/field{fieldNumber}/{readAPIKey}:
    description: Subscribe to a specific field on a channel. Requires the channel's
      Read API Key in the topic.
    parameters:
      channelID:
        schema:
          type: integer
      fieldNumber:
        schema:
          type: integer
          minimum: 1
          maximum: 8
      readAPIKey:
        schema:
          type: string
    subscribe:
      operationId: subscribeFieldFeed
      message:
        $ref: '#/components/messages/FieldValue'
  channels/{channelID}/subscribe/json/{readAPIKey}:
    description: Subscribe to all channel updates as JSON.
    parameters:
      channelID:
        schema:
          type: integer
      readAPIKey:
        schema:
          type: string
    subscribe:
      operationId: subscribeChannelFeedJson
      message:
        $ref: '#/components/messages/ChannelUpdateJson'
components:
  messages:
    ChannelUpdate:
      contentType: application/x-www-form-urlencoded
      payload:
        type: string
        example: field1=23.5&field2=45.2&status=ok
    FieldValue:
      contentType: text/plain
      payload:
        type: string
        example: '23.5'
    ChannelUpdateJson:
      contentType: application/json
      payload:
        type: object
        properties:
          channel_id:
            type: integer
          created_at:
            type: string
            format: date-time
          entry_id:
            type: integer
          field1:
            type: string
          field2:
            type: string
          field3:
            type: string
          field4:
            type: string
          field5:
            type: string
          field6:
            type: string
          field7:
            type: string
          field8:
            type: string
  securitySchemes:
    MqttUserPassword:
      type: userPassword
      description: MQTT device credentials (Client ID, Username, Password) created
        in the ThingSpeak portal under Devices > MQTT.