Source: https://next-auth.js.org/adapters/fauna

The Auth.js project is now part of Better Auth .

Getting Started Adapters FaunaDB

Fauna Adapter

Resources

Fauna documentation

Setup

Installation

npmpnpmyarnbun

npm install @auth/fauna-adapter fauna

pnpm add @auth/fauna-adapter fauna

yarn add @auth/fauna-adapter fauna

bun add @auth/fauna-adapter fauna

Environment Variables

AUTH_FAUNA_CLIENT=http://localhost:8443
AUTH_FAUNA_SECRET=abc123

Configuration

Next.jsQwikSvelteKitExpress

./auth.ts

import NextAuth from "next-auth"
import { Client } from "fauna"
import { FaunaAdapter } from "@auth/fauna-adapter"
 
const client = new Client({
  secret: process.env.AUTH_FAUNA_SECRET,
  endpoint: new URL(process.env.AUTH_FAUNA_CLIENT)
})
 
export { handlers, auth, signIn, signOut } = NextAuth({
  providers: [],
  adapter: FaunaAdapter(client)
})

/src/routes/plugin@auth.ts

import { QwikAuth$ } from "@auth/qwik"
import { Client } from "fauna"
import { FaunaAdapter } from "@auth/fauna-adapter"
 
const client = new Client({
  secret: import.meta.env.AUTH_FAUNA_SECRET,
  endpoint: new URL(import.meta.env.AUTH_FAUNA_CLIENT),
})
 
export const { onRequest, useSession, useSignIn, useSignOut } = QwikAuth$(
  () => ({
    providers: [],
    adapter: FaunaAdapter(client),
  })
)

./src/auth.ts

import { SvelteKitAuth } from "@auth/sveltekit"
import { Client } from "fauna"
import { FaunaAdapter } from "@auth/fauna-adapter"
 
const client = new Client({
  secret: process.env.AUTH_FAUNA_SECRET,
  endpoint: new URL(process.env.AUTH_FAUNA_CLIENT)
})
 
export { handle, signIn, signOut } = SvelteKitAuth({
  providers: [],
  adapter: FaunaAdapter(client)
})

./src/routes/auth.route.ts

import { ExpressAuth } from "@auth/express"
import { Client } from "fauna"
import { FaunaAdapter } from "@auth/fauna-adapter"
 
const app = express()
 
const client = new Client({
  secret: process.env.AUTH_FAUNA_SECRET,
  endpoint: new URL(process.env.AUTH_FAUNA_CLIENT),
})
 
app.set("trust proxy", true)
app.use(
  "/auth/*",
  ExpressAuth({
    providers: [],
    adapter: FaunaAdapter(client),
  })
)

Migrating to v2

In @auth/adapter-fauna@2.0.0, we’ve renamed the collections to use an uppercase naming pattern in accordance with the Fauna best practices. If you’re migrating from v1, you’ll need to rename your collections to match the new naming scheme. Additionally, we’ve renamed the indexes to match the new method-like index names (i.e. account_by_user_id to Account.byUserId). For more information on migrating your Fauna schema, see their migration guide here

Migration Example

Schema

Run the following commands inside of the Shell tab in the Fauna dashboard to setup the appropriate collections and indexes.

authjs-fauna-adapter-schema.fql

Collection.create({
  name: "Account",
  indexes: {
    byUserId: {
      terms: [\
        { field: "userId" }\
      ]
    },
    byProviderAndProviderAccountId: {
      terms [\
        { field: "provider" },\
        { field: "providerAccountId" }\
      ]
    },
  }
})
Collection.create({
  name: "Session",
  constraints: [\
    {\
      unique: ["sessionToken"],\
      status: "active",\
    }\
  ],
  indexes: {
    bySessionToken: {
      terms: [\
        { field: "sessionToken" }\
      ]
    },
    byUserId: {
      terms [\
        { field: "userId" }\
      ]
    },
  }
})
Collection.create({
  name: "User",
  constraints: [\
    {\
      unique: ["email"],\
      status: "active",\
    }\
  ],
  indexes: {
    byEmail: {
      terms [\
        { field: "email" }\
      ]
    },
  }
})
Collection.create({
  name: "VerificationToken",
  indexes: {
    byIdentifierAndToken: {
      terms [\
        { field: "identifier" },\
        { field: "token" }\
      ]
    },
  }
})

Custom Collection Names

If you want to use custom collection names, you can pass them as an option to the adapter, like this:

FaunaAdapter(client, {
  collectionNames: {
    user: "CustomUser",
    account: "CustomAccount",
    session: "CustomSession",
    verificationToken: "CustomVerificationToken",
  },
})

Make sure the collection names you pass to the provider match the collection names of your Fauna database.

Last updated on September 28, 2025

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