Auth Overview

StartupKit authentication is built on Better Auth, a flexible authentication framework for TypeScript.

What StartupKit Provides

@startupkit/auth adds convenience utilities on top of Better Auth:

Server utilities - withAuth(), requireAuth() for Server Components
React hooks - useAuth() for client components
Context provider - AuthProvider with analytics integration

Quick Example

Server Component:

import { withAuth } from "@repo/auth/server"

export default async function Dashboard() {
  const { user } = await withAuth()
  
  if (!user) return <SignInPrompt />
  
  return <div>Welcome, {user.name}</div>
}

Client Component:

"use client"

import { useAuth } from "@repo/auth"

export function Header() {
  const { isAuthenticated, user, logout } = useAuth()

  if (!isAuthenticated) return <a href="/sign-in">Sign In</a>

  return (
    <div>
      <span>{user?.name}</span>
      <button onClick={logout}>Sign Out</button>
    </div>
  )
}

API Reference

Server (`@repo/auth/server`)

Export	Description
`withAuth()`	Get current session (returns `{ user, session }` or nulls)
`requireAuth()`	Get session or redirect to sign-in
`handler()`	Create Next.js API route handler

Client (`@repo/auth`)

Export	Description
`useAuth()`	Hook for auth state and methods
`AuthProvider`	Context provider for auth
`authClient`	Better Auth client instance

Authentication Providers

Better Auth supports many authentication methods including Email OTP, Google, GitHub, Apple, and more. See the Better Auth Providers documentation for the full list.

The Configuration page shows how to set up Email OTP and Google as examples.

Next Steps

Configuration - Set up auth in your monorepo
requireAuth - Protect pages with redirect
withAuth - Get session for conditional rendering
useAuth - Client-side auth hook