Auth

Use Supabase Auth with React

Learn how to use Supabase Auth with React.js.

1

Create a new Supabase project

Launch a new project in the Supabase Dashboard.

Your new database has a table for storing your users. You can see that this table is currently empty by running some SQL in the SQL Editor.

SQL_EDITOR
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select * from auth.users;
2

Create a React app

Create a React app using a Vite template.

Terminal
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npm create vite@latest my-app -- --template react
3

Install the Supabase client library

Navigate to the React app and install the Supabase libraries.

Terminal
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cd my-app && npm install @supabase/supabase-js
4

Declare Supabase Environment Variables

Rename .env.example to .env.local and populate with your Supabase connection variables:

Project URL
Publishable key
Anon key
.env.local
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VITE_SUPABASE_URL=your-project-url
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VITE_SUPABASE_PUBLISHABLE_DEFAULT_KEY=your-publishable-key-or-anon-key
View source

You can also get the Project URL and key from the project's Connect dialog.

Read the API keys docs for a full explanation of all key types and their uses.

5

Set up your login component

In App.jsx, create a Supabase client using your Project URL and key.

The code uses the getClaims method in App.jsx to validate the local JWT before showing the signed-in user.

src/App.jsx
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import './index.css'
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import { useState, useEffect } from 'react'
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import { createClient } from '@supabase/supabase-js'
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const supabase = createClient(
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  import.meta.env.VITE_SUPABASE_URL,
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  import.meta.env.VITE_SUPABASE_PUBLISHABLE_DEFAULT_KEY
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)
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export default function App() {
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  const [loading, setLoading] = useState(false)
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  const [email, setEmail] = useState('')
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  const [claims, setClaims] = useState(null)
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  // Check URL params on initial render
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  const params = new URLSearchParams(window.location.search)
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  const hasTokenHash = params.get('token_hash')
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  const [verifying, setVerifying] = useState(!!hasTokenHash)
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  const [authError, setAuthError] = useState(null)
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  const [authSuccess, setAuthSuccess] = useState(false)
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  useEffect(() => {
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    // Check if we have token_hash in URL (magic link callback)
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    const params = new URLSearchParams(window.location.search)
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    const token_hash = params.get('token_hash')
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    const type = params.get('type')
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    if (token_hash) {
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      // Verify the OTP token
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      supabase.auth
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        .verifyOtp({
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          token_hash,
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          type: type || 'email',
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        })
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        .then(({ error }) => {
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          if (error) {
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            setAuthError(error.message)
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          } else {
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            setAuthSuccess(true)
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            // Clear URL params
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            window.history.replaceState({}, document.title, '/')
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          }
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          setVerifying(false)
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        })
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    }
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    // Check for existing session using getClaims
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    supabase.auth.getClaims().then(({ data: { claims } }) => {
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      setClaims(claims)
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    })
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    // Listen for auth changes
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    const {
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      data: { subscription },
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    } = supabase.auth.onAuthStateChange(() => {
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      supabase.auth.getClaims().then(({ data: { claims } }) => {
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        setClaims(claims)
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      })
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    })
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    return () => subscription.unsubscribe()
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  }, [])
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  const handleLogin = async (event) => {
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    event.preventDefault()
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    setLoading(true)
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    const { error } = await supabase.auth.signInWithOtp({
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      email,
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      options: {
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        emailRedirectTo: window.location.origin,
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      },
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    })
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    if (error) {
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      alert(error.error_description || error.message)
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    } else {
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      alert('Check your email for the login link!')
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    }
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    setLoading(false)
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  }
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  const handleLogout = async () => {
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    await supabase.auth.signOut()
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    setClaims(null)
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  }
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  // Show verification state
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  if (verifying) {
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    return (
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      <div>
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        <h1>Authentication</h1>
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        <p>Confirming your magic link...</p>
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        <p>Loading...</p>
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      </div>
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    )
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  }
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  // Show auth error
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  if (authError) {
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    return (
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      <div>
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        <h1>Authentication</h1>
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        <p>āœ— Authentication failed</p>
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        <p>{authError}</p>
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        <button
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          onClick={() => {
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            setAuthError(null)
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            window.history.replaceState({}, document.title, '/')
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          }}
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        >
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          Return to login
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        </button>
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      </div>
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    )
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  }
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  // Show auth success (briefly before claims load)
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  if (authSuccess && !claims) {
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    return (
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      <div>
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        <h1>Authentication</h1>
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        <p>āœ“ Authentication successful!</p>
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        <p>Loading your account...</p>
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      </div>
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    )
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  }
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  // If user is logged in, show welcome screen
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  if (claims) {
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    return (
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      <div>
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        <h1>Welcome!</h1>
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        <p>You are logged in as: {claims.email}</p>
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        <button onClick={handleLogout}>Sign Out</button>
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      </div>
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    )
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  }
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  // Show login form
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  return (
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    <div>
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      <h1>Supabase + React</h1>
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      <p>Sign in via magic link with your email below</p>
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      <form onSubmit={handleLogin}>
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        <input
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          type="email"
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          placeholder="Your email"
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          value={email}
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          required={true}
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          onChange={(e) => setEmail(e.target.value)}
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        />
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        <button disabled={loading}>
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          {loading ? <span>Loading</span> : <span>Send magic link</span>}
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        </button>
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      </form>
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    </div>
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  )
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}
View source
6

Customize email template

Before proceeding, change the email template to support support a server-side authentication flow that sends a token hash:

  • Go to the Auth templates page in your dashboard.
  • Select the Confirm sign up template.
  • Change {{ .ConfirmationURL }} to {{ .SiteURL }}?token_hash={{ .TokenHash }}&type=email.
  • Change your Site URL to https://localhost:5173
7

Start the app

Start the app, go to http://localhost:5173 in a browser, and open the browser console and you should be able to register and log in.

Terminal
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npm run dev