[Home](./index.md) > [@firebase/auth](./auth.md) > [FactorId](./auth.factorid.md) ## FactorId enum An enum of factors that may be used for multifactor authentication. Signature: ```typescript export declare const enum FactorId ``` ## Enumeration Members | Member | Value | Description | | --- | --- | --- | | PHONE | "phone" | Phone as second factor |