Events Reference

Events are data payloads published by devices. Each device definition declares the event types it can emit, along with the schema for each event’s payload. Events flow from devices through RabbitMQ to Vesbite, where they can trigger workflows or be viewed in the UI.

Event Structure

Every event defined on a device has the following properties:

Event Flow

Device              RabbitMQ                 Vesbite Server          Workflows
  |                    |                          |                      |
  |-- publish event -->|                          |                      |
  |                    |-- route to queue -------->|                      |
  |                    |                          |-- publish MassTransit |
  |                    |                          |   DeviceEvent ------->|
  |                    |                          |                      |-- trigger matching
  |                    |                          |                      |   workflow instances

1. The device publishes an event to RabbitMQ on the topic exchange vesbite.devices with routing key devices.{deviceId}.events.{eventType}.
2. The Vesbite event listener consumes the message from the vesbite-device-events queue.
3. The listener extracts the tenantId and payload from the message, wraps them in a DeviceEvent, and publishes it to MassTransit.
4. Any workflow with a matching Device Event trigger evaluates and, if conditions are met, begins execution.

Event Payload Envelope

The raw message the device publishes contains an envelope:

{
  "tenantId": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
  "deviceId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "payload": {
    "epc": "E2801170000002145A8B6021",
    "rssi": -52,
    "antenna": 1
  }
}

The payload field contains the event-specific data defined by the device’s payloadSchema. Vesbite extracts this inner payload before passing it to workflows.

Common RFID Reader Events

tagread

Emitted when a single RFID tag is read by the reader.

Payload:

Example payload:

{
  "epc": "E2801170000002145A8B6021",
  "tid": "E2801170200060A714011811",
  "rssi": -52,
  "antenna": 1,
  "readCount": 3,
  "timestamp": "2026-03-20T10:30:00.123Z"
}

tagreads

Emitted as a batch when the reader reports multiple tags at once. This is the more common event for high-throughput reading.

Payload:

Example payload:

{
  "tags": [
    { "epc": "E2801170000002145A8B6021", "tid": "E2801170200060A714011811", "rssi": -52, "antenna": 1, "readCount": 3 },
    { "epc": "E280117000000214CC405F22", "tid": "E2801170200060A714011812", "rssi": -48, "antenna": 2, "readCount": 1 }
  ],
  "count": 2,
  "timestamp": "2026-03-20T10:30:01.000Z"
}

gpiochange

Emitted when a General Purpose Input (GPI) pin changes state.

Payload:

Example payload:

{
  "pin": 1,
  "state": true,
  "previousState": false,
  "timestamp": "2026-03-20T10:30:05.000Z"
}

Consuming Events in Workflows

As a Trigger

Add a Device Event trigger node to your workflow. Select the device definition and event type. When that event fires, the workflow starts and the event payload is available as the trigger’s output.

Optionally filter to a specific device by selecting it in the Device dropdown. Leave it empty to trigger on events from any device of that type.

Accessing Event Data

In downstream workflow nodes, access the event payload via expressions:

{{ output("triggerActivityId").epc }}
{{ output("triggerActivityId").rssi }}
{{ output("triggerActivityId").antenna }}

For batch events:

{{ output("triggerActivityId").tags }}
{{ output("triggerActivityId").count }}

The trigger output contains the unwrapped payload fields directly – there is no extra payload wrapper in the expression context.

See Also

• Actions Reference – Commands sent to devices
• Settings Reference – Configurable device parameters
• Workflow Nodes Reference – Device Event trigger node
• Vex Expressions Reference – Accessing event data in expressions