Home > @firebase/auth > signInWithCustomToken

signInWithCustomToken() function

Asynchronously signs in using a custom token.

Signature:

export declare function signInWithCustomToken(auth: Auth, customToken: string): Promise<UserCredential>;

Parameters

Parameter	Type	Description
auth	Auth	The Auth instance.
customToken	string	The custom token to sign in with.

Returns:

Promise<UserCredential>

Description

Custom tokens are used to integrate Firebase Auth with existing auth systems, and must be generated by an auth backend using the createCustomToken method in the Admin SDK .

Fails with an error if the token is invalid, expired, or not accepted by the Firebase Auth service.