# Subscribe to participant state change events in Amazon Connect Agent Workspace
onParticipantStateChanged()

Subscribes to participant state change events. This event fires when a participant's state changes (e.g., from connecting to connected, or to hold).

 **Signature** 

```
onParticipantStateChanged(handler: ParticipantStateChangedHandler, participantId?: string): void
```

 **Usage** 

```
    const handleStateChanged = (event) => {
    console.log(
    `Participant ${event.participantId} state changed to: ${event.state.value}`
    );

    if (event.state.value === "connected") {
    console.log("Participant is now connected");
    } else if (event.state.value === "hold") {
    console.log("Participant is now on hold");
    }
    };

    // Subscribe to all participants
    contactClient.onParticipantStateChanged(handleStateChanged);

    // Or subscribe to a specific participant
    contactClient.onParticipantStateChanged(handleStateChanged, "participant-456");
```

 **Input** 


|  **Parameter**  |  **Type**  |  **Description**  | 
| --- | --- | --- | 
| handler Required | ParticipantStateChangedHandler | Event handler function to call when participant states change | 
| participantId | string | Optional participant ID to filter events for a specific participant | 

 **Event Structure - ParticipantStateChanged** 

The handler receives a ParticipantStateChanged event with:
+ `participantId`: string - The ID of the participant whose state changed
+ `state`: ParticipantState - The new state of the participant

 **Permissions required:** 

```
Contact.Details.View
```