[Home](./index.md) > [@firebase/auth-types](./auth-types.md) > [PhoneAuthProvider](./auth-types.phoneauthprovider.md) > [(constructor)](./auth-types.phoneauthprovider._constructor_.md) ## PhoneAuthProvider.(constructor) Constructs a new instance of the `PhoneAuthProvider` class Signature: ```typescript constructor(auth?: Auth | null); ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | auth | [Auth](./auth-types.auth.md) \| null | The Firebase Auth instance in which sign-ins should occur. | ## Remarks Uses the default Auth instance if unspecified.