nuxt-better-auth

SKILL.md

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