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@auth/core

Experimental

@auth/core is under active development.

This is the main entry point to the Auth.js library.

Based on the Request and Response Web standard APIs. Primarily used to implement framework-specific packages, but it can also be used directly.

Installation​

npm install @auth/core

Usage​

import { Auth } from "@auth/core"

const request = new Request("https://example.com")
const response = await Auth(request, {...})

console.log(response instanceof Response) // true

Resources​

Auth()​

Auth(request, config)​

Auth(request, config): Promise< ResponseInternal >

Core functionality provided by Auth.js.

Receives a standard [Request]([object Object]) and returns a [Response]([object Object]).

Parameters​

▪ request: Request

▪ config: AuthConfig

Returns​

Promise< ResponseInternal >

Example​

import Auth from "@auth/core"

const request = new Request("https://example.com")
const response = await AuthHandler(request, {
  providers: [...],
  secret: "...",
  trustHost: true,
})

See​

Documentation

Auth(request, config)​

Auth(request, config): Promise< Response >

Core functionality provided by Auth.js.

Receives a standard [Request]([object Object]) and returns a [Response]([object Object]).

Parameters​

▪ request: Request

▪ config: Omit< AuthConfig, "raw" >

Returns​

Promise< Response >

Example​

import Auth from "@auth/core"

const request = new Request("https://example.com")
const response = await AuthHandler(request, {
  providers: [...],
  secret: "...",
  trustHost: true,
})

See​

Documentation

AuthConfig​

Configure the Auth method.

Example​

import Auth, { type AuthConfig } from "@auth/core"

export const authConfig: AuthConfig = {...}

const request = new Request("https://example.com")
const response = await AuthHandler(request, authConfig)

See​

Initialization

Properties​

providers​

providers: Provider[]

List of authentication providers for signing in (e.g. Google, Facebook, Twitter, GitHub, Email, etc) in any order. This can be one of the built-in providers or an object with a custom provider.

Default​
[]

adapter​

adapter?: Adapter

You can use the adapter option to pass in your database adapter.

basePath​

basePath?: string

The base path of the Auth.js API endpoints.

Default​
"/auth"

callbacks​

callbacks?: Partial< CallbacksOptions< Profile, Account > >

Callbacks are asynchronous functions you can use to control what happens when an action is performed. Callbacks are extremely powerful, especially in scenarios involving JSON Web Tokens as they allow you to implement access controls without a database and to integrate with external databases or APIs.

cookies​

cookies?: Partial< CookiesOptions >

You can override the default cookie names and options for any of the cookies used by Auth.js. You can specify one or more cookies with custom properties and missing options will use the default values defined by Auth.js. If you use this feature, you will likely want to create conditional behavior to support setting different cookies policies in development and production builds, as you will be opting out of the built-in dynamic policy.

  • ⚠ This is an advanced option. Advanced options are passed the same way as basic options, but may have complex implications or side effects. You should try to avoid using advanced options unless you are very comfortable using them.
Default​
{}

debug​

debug?: boolean

Set debug to true to enable debug messages for authentication and database operations.

Default​
false

events​

events?: Partial< EventCallbacks >

Events are asynchronous functions that do not return a response, they are useful for audit logging. You can specify a handler for any of these events below - e.g. for debugging or to create an audit log. The content of the message object varies depending on the flow (e.g. OAuth or Email authentication flow, JWT or database sessions, etc), but typically contains a user object and/or contents of the JSON Web Token and other information relevant to the event.

Default​
{}

experimental​

experimental?: Record< string, boolean >

Use this option to enable experimental features. When enabled, it will print a warning message to the console.

Note​

Experimental features are not guaranteed to be stable and may change or be removed without notice. Please use with caution.

Default​
{}

jwt​

jwt?: Partial< JWTOptions >

JSON Web Tokens are enabled by default if you have not specified an AuthConfig.adapter. JSON Web Tokens are encrypted (JWE) by default. We recommend you keep this behaviour.

logger​

logger?: Partial< LoggerInstance >

Override any of the logger levels (undefined levels will use the built-in logger), and intercept logs in NextAuth. You can use this option to send NextAuth logs to a third-party logging service.

Example​
// /pages/api/auth/[...nextauth].js
import log from "logging-service"
export default NextAuth({
  logger: {
    error(code, ...message) {
      log.error(code, message)
    },
    warn(code, ...message) {
      log.warn(code, message)
    },
    debug(code, ...message) {
      log.debug(code, message)
    }
  }
})
Default​
console

pages​

pages?: Partial< PagesOptions >

Specify URLs to be used if you want to create custom sign in, sign out and error pages. Pages specified will override the corresponding built-in page.

Default​
{}
Example​
  pages: {
    signIn: '/auth/signin',
    signOut: '/auth/signout',
    error: '/auth/error',
    verifyRequest: '/auth/verify-request',
    newUser: '/auth/new-user'
  }

redirectProxyUrl​

redirectProxyUrl?: string

When set, during an OAuth sign-in flow, the redirect_uri of the authorization request will be set based on this value.

This is useful if your OAuth Provider only supports a single redirect_uri or you want to use OAuth on preview URLs (like Vercel), where you don't know the final deployment URL beforehand.

The url needs to include the full path up to where Auth.js is initialized.

Note​

This will auto-enable the state OAuth2Config.checks on the provider.

Example​
"https://authjs.example.com/api/auth"

You can also override this individually for each provider.

Example​
GitHub({
  ...
  redirectProxyUrl: "https://github.example.com/api/auth"
})
Default​

AUTH_REDIRECT_PROXY_URL environment variable

See also: Guide: Securing a Preview Deployment

secret​

secret?: string | string[]

A random string used to hash tokens, sign cookies and generate cryptographic keys.

To generate a random string, you can use the Auth.js CLI: npx auth secret

Note​

You can also pass an array of secrets, in which case the first secret that successfully decrypts the JWT will be used. This is useful for rotating secrets without invalidating existing sessions. The newer secret should be added to the start of the array, which will be used for all new sessions.

session​

session?: object

Configure your session like if you want to use JWT or a database, how long until an idle session expires, or to throttle write operations in case you are using a database.

Type declaration​
generateSessionToken​

generateSessionToken?: () => string

Generate a custom session token for database-based sessions. By default, a random UUID or string is generated depending on the Node.js version. However, you can specify your own custom string (such as CUID) to be used.

Returns​

string

Default​

randomUUID or randomBytes.toHex depending on the Node.js version

maxAge​

maxAge?: number

Relative time from now in seconds when to expire the session

Default​
2592000 // 30 days
strategy​

strategy?: "jwt" | "database"

Choose how you want to save the user session. The default is "jwt", an encrypted JWT (JWE) in the session cookie.

If you use an adapter however, we default it to "database" instead. You can still force a JWT session by explicitly defining "jwt".

When using "database", the session cookie will only contain a sessionToken value, which is used to look up the session in the database.

Documentation | Adapter | About JSON Web Tokens

updateAge​

updateAge?: number

How often the session should be updated in seconds. If set to 0, session is updated every time.

Default​
86400 // 1 day

theme​

theme?: Theme

Changes the theme of built-in AuthConfig.pages.

trustHost​

trustHost?: boolean

Auth.js relies on the incoming request's host header to function correctly. For this reason this property needs to be set to true.

Make sure that your deployment platform sets the host header safely.

note

Official Auth.js-based libraries will attempt to set this value automatically for some deployment platforms (eg.: Vercel) that are known to set the host header safely.

useSecureCookies​

useSecureCookies?: boolean

When set to true then all cookies set by NextAuth.js will only be accessible from HTTPS URLs. This option defaults to false on URLs that start with http:// (e.g. http://localhost:3000) for developer convenience. You can manually set this option to false to disable this security feature and allow cookies to be accessible from non-secured URLs (this is not recommended).

  • ⚠ This is an advanced option. Advanced options are passed the same way as basic options, but may have complex implications or side effects. You should try to avoid using advanced options unless you are very comfortable using them.

The default is false HTTP and true for HTTPS sites.

raw​

const raw: typeof raw

danger

This option is intended for framework authors.

Auth.js returns a web standard [Response]([object Object]) by default, but if you are implementing a framework you might want to get access to the raw internal response by passing this value to [AuthConfig.raw]([object Object]).

skipCSRFCheck​

const skipCSRFCheck: typeof skipCSRFCheck

danger

This option is intended for framework authors.

Auth.js comes with built-in CSRF protection, but if you are implementing a framework that is already protected against CSRF attacks, you can skip this check by passing this value to [AuthConfig.skipCSRFCheck]([object Object]).