[Home](./index.md) > [@firebase/auth-types](./auth-types.md) > [Auth](./auth-types.auth.md) > [useEmulator](./auth-types.auth.useemulator.md) ## Auth.useEmulator() method Modify this Auth instance to communicate with the Firebase Auth emulator. Signature: ```typescript useEmulator(url: string, options?: { disableWarnings: boolean }): void; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | url | string | The URL at which the emulator is running (eg, 'http://localhost:9099'). | | options | { disableWarnings: boolean } | | Returns: void ## Remarks This must be called synchronously immediately following the first call to [initializeAuth()](./auth.initializeauth.md). Do not use with production credentials as emulator traffic is not encrypted.