onmax/nuxt-better-auth

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

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