WebSocket API

The ThingsBoard WebSocket API provides real-time, bidirectional communication between client applications and the platform. Use it to subscribe to telemetry updates, entity data changes, alarm events, and notifications — all pushed instantly without polling.

Connection

Connect to the WebSocket endpoint:

https://thingsboard.cloud/api/ws

Replace http:// with ws:// or https:// with wss:// depending on your deployment. For self-hosted installations, use the host and port configured for your ThingsBoard instance.

Authentication

After opening the connection, send an authCmd with a JWT token:

{
  "authCmd": {
    "cmdId": 0,
    "token": "YOUR_JWT_TOKEN"
  }
}

Obtain the JWT token from the REST API login endpoint.

The connection times out after 90 seconds of inactivity. The client should send periodic pings or commands to keep it alive.

Message format

Requests

All commands are sent as JSON. You can batch multiple commands in a single message:

{
  "authCmd": { "cmdId": 0, "token": "JWT_TOKEN" },
  "cmds": [
    { "cmdId": 1, "type": "ENTITY_DATA", ... },
    { "cmdId": 2, "type": "ALARM_COUNT", ... }
  ]
}

Each command has a unique cmdId (integer) chosen by the client. Responses reference this ID.

Responses

{
  "cmdId": 1,
  "errorCode": 0,
  "errorMsg": null,
  "cmdUpdateType": "ENTITY_DATA",
  ...
}

Error codes

Code	Name	Description
0	`NO_ERROR`	Success
1	`INTERNAL_ERROR`	Internal server error
2	`BAD_REQUEST`	Invalid command or parameters
3	`UNAUTHORIZED`	Missing or invalid authentication

Command types

Entity data subscription

Subscribe to entity data with filtering, pagination, and real-time updates. See the Entity Data Query API reference for the full list of entity filters, key filters, and query options.

{
  "cmds": [
    {
      "cmdId": 1,
      "type": "ENTITY_DATA",
      "query": {
        "entityFilter": {
          "type": "entityType",
          "entityType": "DEVICE"
        },
        "pageLink": {
          "pageSize": 10,
          "page": 0,
          "sortOrder": {
            "key": { "type": "ENTITY_FIELD", "key": "createdTime" },
            "direction": "DESC"
          }
        },
        "entityFields": [
          { "type": "ENTITY_FIELD", "key": "name" },
          { "type": "ENTITY_FIELD", "key": "type" }
        ],
        "latestValues": [
          { "type": "ATTRIBUTE", "key": "active" }
        ],
        "keyFilters": []
      },
      "latestCmd": {
        "keys": [
          { "type": "TIME_SERIES", "key": "temperature" }
        ]
      }
    }
  ]
}

Initial response contains the full result set in data. Subsequent real-time updates arrive in the update field:

{
  "cmdId": 1,
  "errorCode": 0,
  "cmdUpdateType": "ENTITY_DATA",
  "data": {
    "data": [
      {
        "entityId": { "entityType": "DEVICE", "id": "device-uuid" },
        "latest": {
          "ATTRIBUTE": { "active": { "ts": 1704067200000, "value": "true" } },
          "TIME_SERIES": { "temperature": { "ts": 1704067260000, "value": "42.5" } }
        }
      }
    ],
    "totalPages": 1,
    "totalElements": 1,
    "hasNext": false
  }
}

Time series history — add historyCmd or tsCmd to fetch historical data or subscribe to a rolling time window:

{
  "cmds": [
    {
      "cmdId": 2,
      "type": "ENTITY_DATA",
      "query": { ... },
      "tsCmd": {
        "keys": ["temperature", "humidity"],
        "startTs": 1704067200000,
        "timeWindow": 3600000
      }
    }
  ]
}

Entity count

Get a live count of entities matching a filter:

{
  "cmds": [
    {
      "cmdId": 3,
      "type": "ENTITY_COUNT",
      "query": {
        "entityFilter": {
          "type": "entityType",
          "entityType": "DEVICE"
        },
        "keyFilters": []
      }
    }
  ]
}

Response:

{
  "cmdId": 3,
  "errorCode": 0,
  "cmdUpdateType": "COUNT_DATA",
  "count": 42
}

Alarm data subscription

Subscribe to alarms with filtering and real-time updates. See the Alarm Query API reference for alarm-specific filters, severity and status values, and query options.

{
  "cmds": [
    {
      "cmdId": 4,
      "type": "ALARM_DATA",
      "query": {
        "entityFilter": {
          "type": "entityType",
          "entityType": "DEVICE"
        },
        "pageLink": {
          "pageSize": 10,
          "page": 0,
          "sortOrder": {
            "key": { "type": "ALARM_FIELD", "key": "createdTime" },
            "direction": "DESC"
          }
        },
        "alarmFields": [
          { "type": "ALARM_FIELD", "key": "createdTime" },
          { "type": "ALARM_FIELD", "key": "type" },
          { "type": "ALARM_FIELD", "key": "severity" },
          { "type": "ALARM_FIELD", "key": "status" }
        ],
        "keyFilters": []
      }
    }
  ]
}

Alarm count

{
  "cmds": [
    {
      "cmdId": 5,
      "type": "ALARM_COUNT",
      "query": {
        "entityFilter": {
          "type": "entityType",
          "entityType": "DEVICE"
        },
        "keyFilters": []
      }
    }
  ]
}

Response:

{
  "cmdId": 5,
  "errorCode": 0,
  "cmdUpdateType": "ALARM_COUNT_DATA",
  "count": 15
}

Alarm status

Monitor whether any active alarms match the given criteria for a specific entity:

{
  "cmds": [
    {
      "cmdId": 6,
      "type": "ALARM_STATUS",
      "originatorId": { "entityType": "DEVICE", "id": "device-uuid" },
      "typeList": ["HIGH_TEMPERATURE"],
      "severityList": ["CRITICAL", "MAJOR"]
    }
  ]
}

Response:

{
  "cmdId": 6,
  "errorCode": 0,
  "cmdUpdateType": "ALARM_STATUS",
  "active": true
}

Pass null for typeList or severityList to match all alarm types or severities.

Notifications

Subscribe to user notifications:

{
  "cmds": [
    {
      "cmdId": 7,
      "type": "NOTIFICATIONS",
      "limit": 10
    }
  ]
}

Response:

{
  "cmdId": 7,
  "errorCode": 0,
  "cmdUpdateType": "NOTIFICATIONS",
  "totalUnreadCount": 5,
  "notifications": [
    {
      "id": "notification-uuid",
      "createdTime": 1704067200000,
      "type": "ALARM",
      "text": "High temperature detected",
      "read": false
    }
  ]
}

Get unread count only:

{ "cmds": [{ "cmdId": 8, "type": "NOTIFICATIONS_COUNT" }] }

Mark as read:

{
  "cmds": [
    {
      "cmdId": 9,
      "type": "MARK_NOTIFICATIONS_AS_READ",
      "notifications": ["notification-uuid-1", "notification-uuid-2"]
    }
  ]
}

Mark all as read:

{ "cmds": [{ "cmdId": 10, "type": "MARK_ALL_NOTIFICATIONS_AS_READ" }] }

Legacy telemetry subscriptions

These v1 commands subscribe to a single entity’s telemetry or attributes directly (without the Entity Data Query):

Attributes:

{
  "cmds": [
    {
      "cmdId": 11,
      "type": "ATTRIBUTES",
      "entityType": "DEVICE",
      "entityId": "device-uuid",
      "keys": "temperature,humidity",
      "scope": "SERVER_SCOPE"
    }
  ]
}

Time series:

{
  "cmds": [
    {
      "cmdId": 12,
      "type": "TIMESERIES",
      "entityType": "DEVICE",
      "entityId": "device-uuid",
      "keys": "temperature",
      "startTs": 1704067200000,
      "timeWindow": 3600000,
      "interval": 60000,
      "limit": 100,
      "agg": "AVG"
    }
  ]
}

Time series history (one-time fetch, no subscription):

{
  "cmds": [
    {
      "cmdId": 13,
      "type": "TIMESERIES_HISTORY",
      "entityType": "DEVICE",
      "entityId": "device-uuid",
      "keys": "temperature",
      "startTs": 1704067200000,
      "endTs": 1704153600000,
      "interval": 3600000,
      "limit": 100,
      "agg": "AVG"
    }
  ]
}

Aggregation types: NONE, AVG, MIN, MAX, SUM, COUNT.

Unsubscribing

For v2 commands (Entity Data, Alarm Data, etc.), send an unsubscribe command with the same cmdId:

{
  "cmds": [
    { "cmdId": 1, "type": "ENTITY_DATA_UNSUBSCRIBE" },
    { "cmdId": 4, "type": "ALARM_DATA_UNSUBSCRIBE" }
  ]
}

Unsubscribe types: ENTITY_DATA_UNSUBSCRIBE, ENTITY_COUNT_UNSUBSCRIBE, ALARM_DATA_UNSUBSCRIBE, ALARM_COUNT_UNSUBSCRIBE, ALARM_STATUS_UNSUBSCRIBE, NOTIFICATIONS_UNSUBSCRIBE.

For v1 commands (Attributes, Time Series), resend the original command with "unsubscribe": true.

Complete message flow

A typical session:

Open WebSocket connection to wss://host/api/ws
Authenticate — send authCmd with JWT token
Subscribe — send one or more commands in cmds
Receive initial data — server responds with full result
Receive updates — server pushes changes as they happen
Unsubscribe — send unsubscribe command when done
Close connection

// 1. Auth + subscribe in one message
{
  "authCmd": { "cmdId": 0, "token": "JWT_TOKEN" },
  "cmds": [
    {
      "cmdId": 1,
      "type": "ENTITY_COUNT",
      "query": {
        "entityFilter": { "type": "entityType", "entityType": "DEVICE" },
        "keyFilters": []
      }
    }
  ]
}

// 2. Server responds with count
// { "cmdId": 1, "errorCode": 0, "cmdUpdateType": "COUNT_DATA", "count": 42 }

// 3. Server pushes update when count changes
// { "cmdId": 1, "errorCode": 0, "cmdUpdateType": "COUNT_DATA", "count": 43 }

// 4. Unsubscribe
{ "cmds": [{ "cmdId": 1, "type": "ENTITY_COUNT_UNSUBSCRIBE" }] }

WebSocket API

Connection

Authentication

Message format

Requests

Responses

Error codes

Command types

Entity data subscription

Entity count

Alarm data subscription

Alarm count

Alarm status

Notifications

Legacy telemetry subscriptions

Unsubscribing

Complete message flow

See also