> Fetch clean Markdown by appending `.md` to any page URL under https://signalwire.com/docs or requesting it with the HTTP header `Accept: text/markdown`. The root index at https://signalwire.com/docs/llms.txt lists the available documentation indexes.

# userId$

> Observable of the participant's user ID.

```ts
get userId$(): Observable<string | undefined>
```

Observable of the participant's user ID.

## **Inherited from**

[`Participant`](/docs/browser-sdk/v4/reference/participant).[`userId$`](/docs/browser-sdk/v4/reference/participant#userid-1)

## userId

```ts
get userId(): string | undefined
```

User ID of this participant, or `undefined` if not available.

## **Inherited from**

[`Participant`](/docs/browser-sdk/v4/reference/participant).[`userId`](/docs/browser-sdk/v4/reference/participant#userid)

## **Examples**

```ts
selfParticipant.userId$.subscribe((userId) => {
  console.log('userId:', userId);
});
```