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@auth/firebase-adapter

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

Installation​

npm install @auth/firebase-adapter firebase-admin

FirestoreAdapter()​

FirestoreAdapter(config?): Adapter

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.

Parameters​

▪ config?: FirebaseAdapterConfig | Firestore

Returns​

Adapter

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),
 // ...
})

initFirestore()​

initFirestore(options): Firestore

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.

Parameters​

▪ options: AppOptions & { name: string; }= {}

Returns​

Firestore

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,
 })
})

FirebaseAdapterConfig​

Configure the Firebase Adapter.

Extends​

  • AppOptions

Properties​

name​

name?: string;

The name of the app passed to initializeApp().

namingStrategy​

namingStrategy?: "snake_case" | "default";

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" })
 // ...
})