@auth/firebase-adapter

Official Firebase adapter for Auth.js / NextAuth.js, using the Firebase Admin SDK and Firestore.

Installation

npm

npm install @auth/firebase-adapter firebase-admin

yarn

yarn add @auth/firebase-adapter firebase-admin

pnpm

pnpm add @auth/firebase-adapter firebase-admin

FirestoreAdapter()

Setup

First, create a Firebase project and generate a service account key. Visit: https://console.firebase.google.com/u/0/project/{project-id}/settings/serviceaccounts/adminsdk (replace {project-id} with your project's id)

Now you have a few options to authenticate with the Firebase Admin SDK in your app:

Environment variables

• Download the service account key and save it in your project. (Make sure to add the file to your .gitignore!)
• Add GOOGLE_APPLICATION_CREDENTIALS to your environment variables and point it to the service account key file.
• The adapter will automatically pick up the environment variable and use it to authenticate with the Firebase Admin SDK.

Example

pages/api/auth/[...nextauth].ts

import NextAuth from "next-auth";
import { FirestoreAdapter } from "@auth/firebase-adapter";

export default NextAuth({
  adapter: FirestoreAdapter(),
  // ...
});

Service account values

• Download the service account key to a temporary location. (Make sure to not commit this file to your repository!)
• Add the following environment variables to your project: FIREBASE_PROJECT_ID, FIREBASE_CLIENT_EMAIL, FIREBASE_PRIVATE_KEY.
• Pass the config to the adapter, using the environment variables as shown in the example below.

Example

pages/api/auth/[...nextauth].ts

import NextAuth from "next-auth";
import { FirestoreAdapter } from "@auth/firebase-adapter";
import { cert } from "firebase-admin/app";

export default NextAuth({
  adapter: FirestoreAdapter({
    credential: cert({
      projectId: process.env.FIREBASE_PROJECT_ID,
      clientEmail: process.env.FIREBASE_CLIENT_EMAIL,
      privateKey: process.env.FIREBASE_PRIVATE_KEY,
    }),
  }),
  // ...
});

Using an existing Firestore instance

If you already have a Firestore instance, you can pass that to the adapter directly instead.

note

When passing an instance and in a serverless environment, remember to handle duplicate app initialization.

tip

You can use the initFirestore utility to initialize the app and get an instance safely.

Example

pages/api/auth/[...nextauth].ts

import NextAuth from "next-auth";
import { FirestoreAdapter } from "@auth/firebase-adapter";
import { firestore } from "lib/firestore";

export default NextAuth({
  adapter: FirestoreAdapter(firestore),
  // ...
});

FirestoreAdapter(config?: FirebaseAdapterConfig | Firestore): Adapter

Parameters

Parameter	Type
config?	FirebaseAdapterConfig | Firestore

Returns

Adapter

---

initFirestore()

Utility function that helps making sure that there is no duplicate app initialization issues in serverless environments. If no parameter is passed, it will use the GOOGLE_APPLICATION_CREDENTIALS environment variable to initialize a Firestore instance.

Example

lib/firestore.ts

import { initFirestore } from "@auth/firebase-adapter";
import { cert } from "firebase-admin/app";

export const firestore = initFirestore({
  credential: cert({
    projectId: process.env.FIREBASE_PROJECT_ID,
    clientEmail: process.env.FIREBASE_CLIENT_EMAIL,
    privateKey: process.env.FIREBASE_PRIVATE_KEY,
  }),
});

initFirestore(options: AppOptions & {name?: string;} = {}): Firestore

Parameters

Parameter	Type
options	AppOptions & {name?: string;}

Returns

Firestore

---

FirebaseAdapterConfig

Configure the Firebase Adapter.

Properties

name?

name: string

The name of the app passed to initializeApp().

namingStrategy?

namingStrategy: "snake_case"

Use this option if mixed snake_case and camelCase field names in the database is an issue for you. Passing snake_case will convert all field and collection names to snake_case. E.g. the collection verificationTokens will be verification_tokens, and fields like emailVerified will be email_verified instead.

Example

pages/api/auth/[...nextauth].ts

import NextAuth from "next-auth";
import { FirestoreAdapter } from "@auth/firebase-adapter";

export default NextAuth({
  adapter: FirestoreAdapter({ namingStrategy: "snake_case" }),
  // ...
});

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