[Home](./index.md) > [@firebase/auth](./auth.md) > [AdditionalUserInfo](./auth.additionaluserinfo.md) ## AdditionalUserInfo interface A structure containing additional user information from a federated identity provider. Signature: ```typescript export interface AdditionalUserInfo ``` ## Properties | Property | Type | Description | | --- | --- | --- | | [isNewUser](./auth.additionaluserinfo.isnewuser.md) | boolean | Whether the user is new (created via sign-up) or existing (authenticated using sign-in). | | [profile](./auth.additionaluserinfo.profile.md) | Record<string, unknown> \| null | Map containing IDP-specific user data. | | [providerId](./auth.additionaluserinfo.providerid.md) | string \| null | Identifier for the provider used to authenticate this user. | | [username?](./auth.additionaluserinfo.username.md) | string \| null | (Optional) The username if the provider is GitHub or Twitter. |