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# extractSipUsername

> Static utility that extracts the username portion from a SIP URI in a request body.

[ref-registerroutingcallback]: /docs/server-sdks/reference/typescript/agents/swml-service/register-routing-callback

Static utility method that extracts the username portion from the `call.to`
field of a parsed request body. Handles three input formats:

* `sip:username@domain` (or `sips:...`) -- strips the scheme and `@domain`
  suffix, returning the username
* `tel:+1234567890` -- strips the `tel:` scheme, returning the phone number
* Plain string -- returned as-is

Commonly paired with
[`registerRoutingCallback()`][ref-registerroutingcallback] to route SIP traffic
based on the dialed user.

## **Parameters**

**`requestBody`** `Record<string, unknown>` — required

The parsed JSON body from an incoming request. Expected to contain a
`call.to` field with a SIP URI, TEL URI, or phone number string.

---

## **Returns**

`string | null` -- The extracted username or phone number, or `null` if the
`call.to` field is missing or cannot be parsed.

## **Examples**

### Extract from SIP URI

```typescript {4}
import { SWMLService } from '@signalwire/sdk';

const body = { call: { to: 'sip:sales@example.sip.signalwire.com' } };
const username = SWMLService.extractSipUsername(body);
// "sales"
```

### Extract from TEL URI

```typescript {4}
import { SWMLService } from '@signalwire/sdk';

const body = { call: { to: 'tel:+15551234567' } };
const number = SWMLService.extractSipUsername(body);
// "+15551234567"
```

> Static utility that extracts the username portion from a SIP URI in a request body.