Nuxt Better Auth

Authentication module for Nuxt 4+ built on Better Auth. Provides composables, server utilities, and route protection.

Alpha Status: This module is currently in alpha (v0.0.2-alpha.19) and not recommended for production use. APIs may change.

When to Use

• Installing/configuring @onmax/nuxt-better-auth
• Implementing login/signup/signout flows
• Protecting routes (client and server)
• Accessing user session in API routes
• Integrating Better Auth plugins (admin, passkey, 2FA)
• Setting up database with NuxtHub
• Using clientOnly mode for external auth backends
• Adding i18n support with @nuxtjs/i18n

For Nuxt patterns: use nuxt skill For NuxtHub database: use nuxthub skill

Available Guidance

File	Topics
references/installation.md	Module setup, env vars, config files
references/client-auth.md	useUserSession, signIn/signUp/signOut, BetterAuthState, safe redirects
references/server-auth.md	serverAuth, getUserSession, requireUserSession
references/route-protection.md	routeRules, definePageMeta, middleware
references/plugins.md	Better Auth plugins (admin, passkey, 2FA)
references/database.md	NuxtHub integration, Drizzle schema, custom tables with FKs
references/client-only.md	External auth backend, clientOnly mode, CORS
references/types.md	AuthUser, AuthSession, type augmentation

Loading Files

Consider loading these reference files based on your task:

• references/installation.md - if installing or configuring the module
• references/client-auth.md - if building login/signup/signout flows
• references/server-auth.md - if protecting API routes or accessing user session server-side
• references/route-protection.md - if using routeRules or definePageMeta for auth
• references/plugins.md - if integrating Better Auth plugins (admin, passkey, 2FA)
• references/database.md - if setting up database with NuxtHub or Drizzle
• references/client-only.md - if using external auth backend with clientOnly mode
• references/types.md - if working with AuthUser, AuthSession, or type augmentation

DO NOT load all files at once. Load only what's relevant to your current task.

Key Concepts

Concept	Description
useUserSession()	Client composable - user, session, loggedIn, signIn/Out methods
requireUserSession()	Server helper - throws 401/403 if not authenticated
auth route mode	'user', 'guest', { user: {...} }, or false
serverAuth()	Get Better Auth instance in server routes

Quick Reference

// Client: useUserSession()
const { user, loggedIn, signIn, signOut } = useUserSession()
await signIn.email({ email, password }, { onSuccess: () => navigateTo('/') })

// Server: requireUserSession()
const { user } = await requireUserSession(event, { user: { role: 'admin' } })

// nuxt.config.ts: Route protection
routeRules: {
  '/admin/**': { auth: { user: { role: 'admin' } } },
  '/login': { auth: 'guest' },
  '/app/**': { auth: 'user' }
}

Resources

• Module Docs
• Better Auth Docs

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Token efficiency: Main skill ~300 tokens, each sub-file ~800-1200 tokens