name	supabase-auth
description	Implements Supabase Authentication with email, OAuth, magic links, and phone auth. Use when building apps with Supabase, needing auth integrated with Row Level Security, or implementing passwordless login.

Supabase Auth

Supabase Auth provides authentication integrated with PostgreSQL Row Level Security. Supports email/password, magic links, OTP, OAuth, and anonymous sign-in.

Quick Start

npm install @supabase/supabase-js

import { createClient } from '@supabase/supabase-js'

const supabase = createClient(
  process.env.NEXT_PUBLIC_SUPABASE_URL!,
  process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!
)

Email/Password Authentication

Sign Up

const { data, error } = await supabase.auth.signUp({
  email: 'user@example.com',
  password: 'secure-password',
  options: {
    data: {
      full_name: 'John Doe',
      avatar_url: 'https://example.com/avatar.png'
    },
    emailRedirectTo: 'https://myapp.com/welcome'
  }
})

if (error) {
  console.error('Sign up error:', error.message)
} else {
  console.log('Check email for confirmation')
}

Sign In

const { data, error } = await supabase.auth.signInWithPassword({
  email: 'user@example.com',
  password: 'secure-password'
})

if (error) {
  console.error('Sign in error:', error.message)
} else {
  console.log('User:', data.user)
  console.log('Session:', data.session)
}

Sign Out

const { error } = await supabase.auth.signOut()

// Sign out from all devices
const { error } = await supabase.auth.signOut({ scope: 'global' })

Magic Link (Passwordless)

const { error } = await supabase.auth.signInWithOtp({
  email: 'user@example.com',
  options: {
    emailRedirectTo: 'https://myapp.com/auth/callback'
  }
})

if (!error) {
  console.log('Check email for magic link')
}

Phone/SMS Authentication

// Send OTP
const { error } = await supabase.auth.signInWithOtp({
  phone: '+1234567890'
})

// Verify OTP
const { data, error } = await supabase.auth.verifyOtp({
  phone: '+1234567890',
  token: '123456',
  type: 'sms'
})

OAuth (Social Login)

Sign In with Provider

const { data, error } = await supabase.auth.signInWithOAuth({
  provider: 'google',
  options: {
    redirectTo: 'https://myapp.com/auth/callback',
    scopes: 'email profile',
    queryParams: {
      access_type: 'offline',
      prompt: 'consent'
    }
  }
})

// Providers: google, github, discord, facebook, twitter,
// apple, azure, gitlab, bitbucket, linkedin, notion, slack, spotify, twitch, zoom

Handle OAuth Callback

// app/auth/callback/route.ts (Next.js App Router)
import { createClient } from '@/lib/supabase/server'
import { NextResponse } from 'next/server'

export async function GET(request: Request) {
  const { searchParams, origin } = new URL(request.url)
  const code = searchParams.get('code')
  const next = searchParams.get('next') ?? '/'

  if (code) {
    const supabase = await createClient()
    const { error } = await supabase.auth.exchangeCodeForSession(code)
    if (!error) {
      return NextResponse.redirect(`${origin}${next}`)
    }
  }

  return NextResponse.redirect(`${origin}/auth/error`)
}

Anonymous Sign In

// Enable in Dashboard: Authentication > Providers > Anonymous

const { data, error } = await supabase.auth.signInAnonymously()

// Convert anonymous to permanent user
const { error: linkError } = await supabase.auth.updateUser({
  email: 'user@example.com',
  password: 'new-password'
})

Session Management

Get Session

// Get current session
const { data: { session } } = await supabase.auth.getSession()

// Get current user
const { data: { user } } = await supabase.auth.getUser()

Listen to Auth Changes

const { data: { subscription } } = supabase.auth.onAuthStateChange(
  (event, session) => {
    console.log('Auth event:', event)
    // Events: SIGNED_IN, SIGNED_OUT, TOKEN_REFRESHED,
    // USER_UPDATED, PASSWORD_RECOVERY

    if (event === 'SIGNED_IN') {
      console.log('User signed in:', session?.user)
    }

    if (event === 'SIGNED_OUT') {
      console.log('User signed out')
    }
  }
)

// Cleanup
subscription.unsubscribe()

Refresh Session

const { data, error } = await supabase.auth.refreshSession()

Password Recovery

Send Reset Email

const { error } = await supabase.auth.resetPasswordForEmail(
  'user@example.com',
  {
    redirectTo: 'https://myapp.com/auth/reset-password'
  }
)

Update Password

// After user clicks reset link and is redirected
const { error } = await supabase.auth.updateUser({
  password: 'new-secure-password'
})

Update User

// Update email (sends confirmation)
const { data, error } = await supabase.auth.updateUser({
  email: 'new@example.com'
})

// Update password
const { data, error } = await supabase.auth.updateUser({
  password: 'new-password'
})

// Update metadata
const { data, error } = await supabase.auth.updateUser({
  data: {
    full_name: 'Jane Doe',
    avatar_url: 'https://example.com/new-avatar.png'
  }
})

Next.js Integration

Server-Side Client

// lib/supabase/server.ts
import { createServerClient } from '@supabase/ssr'
import { cookies } from 'next/headers'

export async function createClient() {
  const cookieStore = await cookies()

  return createServerClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
    {
      cookies: {
        getAll() {
          return cookieStore.getAll()
        },
        setAll(cookiesToSet) {
          try {
            cookiesToSet.forEach(({ name, value, options }) =>
              cookieStore.set(name, value, options)
            )
          } catch {
            // Ignore in Server Components
          }
        },
      },
    }
  )
}

Browser Client

// lib/supabase/client.ts
import { createBrowserClient } from '@supabase/ssr'

export function createClient() {
  return createBrowserClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!
  )
}

Middleware

// middleware.ts
import { createServerClient } from '@supabase/ssr'
import { NextResponse, type NextRequest } from 'next/server'

export async function middleware(request: NextRequest) {
  let response = NextResponse.next({ request })

  const supabase = createServerClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
    {
      cookies: {
        getAll() {
          return request.cookies.getAll()
        },
        setAll(cookiesToSet) {
          cookiesToSet.forEach(({ name, value }) =>
            request.cookies.set(name, value)
          )
          response = NextResponse.next({ request })
          cookiesToSet.forEach(({ name, value, options }) =>
            response.cookies.set(name, value, options)
          )
        },
      },
    }
  )

  // Refresh session
  await supabase.auth.getUser()

  return response
}

export const config = {
  matcher: ['/((?!_next/static|_next/image|favicon.ico).*)'],
}

Protected Server Component

// app/dashboard/page.tsx
import { createClient } from '@/lib/supabase/server'
import { redirect } from 'next/navigation'

export default async function Dashboard() {
  const supabase = await createClient()
  const { data: { user } } = await supabase.auth.getUser()

  if (!user) {
    redirect('/login')
  }

  return <div>Welcome, {user.email}</div>
}

React Hooks

Auth Context

// contexts/auth-context.tsx
'use client'
import { createContext, useContext, useEffect, useState } from 'react'
import { User, Session } from '@supabase/supabase-js'
import { createClient } from '@/lib/supabase/client'

type AuthContextType = {
  user: User | null
  session: Session | null
  loading: boolean
}

const AuthContext = createContext<AuthContextType>({
  user: null,
  session: null,
  loading: true
})

export function AuthProvider({ children }: { children: React.ReactNode }) {
  const [user, setUser] = useState<User | null>(null)
  const [session, setSession] = useState<Session | null>(null)
  const [loading, setLoading] = useState(true)
  const supabase = createClient()

  useEffect(() => {
    supabase.auth.getSession().then(({ data: { session } }) => {
      setSession(session)
      setUser(session?.user ?? null)
      setLoading(false)
    })

    const { data: { subscription } } = supabase.auth.onAuthStateChange(
      (_event, session) => {
        setSession(session)
        setUser(session?.user ?? null)
      }
    )

    return () => subscription.unsubscribe()
  }, [])

  return (
    <AuthContext.Provider value={{ user, session, loading }}>
      {children}
    </AuthContext.Provider>
  )
}

export const useAuth = () => useContext(AuthContext)

Usage

'use client'
import { useAuth } from '@/contexts/auth-context'

export default function Profile() {
  const { user, loading } = useAuth()

  if (loading) return <div>Loading...</div>
  if (!user) return <div>Not logged in</div>

  return <div>Hello, {user.email}</div>
}

Multi-Factor Authentication

Enroll TOTP

// Start enrollment
const { data, error } = await supabase.auth.mfa.enroll({
  factorType: 'totp',
  friendlyName: 'Authenticator App'
})

// data contains:
// - id: factor ID
// - totp.qr_code: QR code SVG
// - totp.secret: manual entry secret
// - totp.uri: otpauth:// URI

// Verify enrollment
const { data: challenge } = await supabase.auth.mfa.challenge({
  factorId: data.id
})

const { data: verify, error } = await supabase.auth.mfa.verify({
  factorId: data.id,
  challengeId: challenge.id,
  code: '123456'
})

Challenge During Login

const { data, error } = await supabase.auth.signInWithPassword({
  email: 'user@example.com',
  password: 'password'
})

if (data.session === null && data.user) {
  // MFA required
  const factors = await supabase.auth.mfa.listFactors()
  const totpFactor = factors.data.totp[0]

  const { data: challenge } = await supabase.auth.mfa.challenge({
    factorId: totpFactor.id
  })

  // Get code from user, then verify
  const { data: session, error } = await supabase.auth.mfa.verify({
    factorId: totpFactor.id,
    challengeId: challenge.id,
    code: userEnteredCode
  })
}

Row Level Security Integration

Auth integrates seamlessly with RLS:

-- Users can only read their own data
CREATE POLICY "Users read own data"
ON profiles FOR SELECT
TO authenticated
USING ((SELECT auth.uid()) = user_id);

-- Check auth in policies
CREATE POLICY "Authenticated users insert"
ON posts FOR INSERT
TO authenticated
WITH CHECK (auth.uid() = author_id);

Admin Operations

Use service role for admin operations:

import { createClient } from '@supabase/supabase-js'

const supabaseAdmin = createClient(
  process.env.SUPABASE_URL!,
  process.env.SUPABASE_SERVICE_ROLE_KEY!,
  {
    auth: {
      autoRefreshToken: false,
      persistSession: false
    }
  }
)

// Admin operations
const { data, error } = await supabaseAdmin.auth.admin.listUsers()

// Create user
const { data, error } = await supabaseAdmin.auth.admin.createUser({
  email: 'user@example.com',
  password: 'password',
  email_confirm: true
})

// Delete user
await supabaseAdmin.auth.admin.deleteUser(userId)

Best Practices

Use SSR package - @supabase/ssr for server-side
Middleware for session refresh - Keep sessions alive
Combine with RLS - Database-level security
Handle auth state changes - Update UI reactively
Use service role carefully - Only server-side, never expose

supabase-auth

Install Skill

SKILL.md