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Supabase Backend as a Service · Lesson

User Registration with Email/Password

Implement standard email and password authentication, including user sign-up, sign-in, and password reset functionalities.

User Registration with Email/Password is a free Supabase Backend as a Service lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Supabase Backend as a Service learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Email/Password Auth Basics

Welcome to user authentication with Supabase! We'll start with the most common method: email and password.

This method allows users to create an account using their email and a chosen password, and then sign in with those credentials.

Supabase Auth Explained

Supabase provides a complete authentication system out-of-the-box. It handles:

  • User registration and login
  • Password hashing and security
  • Session management
  • Email confirmations and password resets

All of this is managed through simple client-side methods.

Initialize Supabase Client

Before we can register or log in users, we need to set up the Supabase client. This client will be our bridge to all Supabase services, including authentication.

You'll need your project's URL and anon (public) key, which you can find in your Supabase dashboard settings.

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

const SUPABASE_URL = 'YOUR_SUPABASE_URL'
const SUPABASE_ANON_KEY = 'YOUR_SUPABASE_ANON_KEY'

const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY)

console.log('Supabase client initialized!')

Registering New Users

To let users create an account, we use the signUp method. This method takes an email and password, and optionally other user metadata.

Supabase handles the secure storage of the password and typically sends a confirmation email to the user.

async function registerUser(email, password) {
  const { data, error } = await supabase.auth.signUp({
    email: email,
    password: password
  })

  if (error) {
    console.error('Sign up error:', error.message)
  } else {
    console.log('User signed up successfully:', data.user.email)
    console.log('Check your email for a confirmation link!')
  }
}

Try User Sign-Up

Let's put the signUp method into a runnable example. This code simulates a new user registration.

In a real app, you'd get the email and password from a form.

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

const SUPABASE_URL = 'https://abcde12345.supabase.co'
const SUPABASE_ANON_KEY = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZSIsInJlZiI6ImFiY2RlMTIzNDUiLCJyb2xlIjoiYW5vbiIsImlhdCI6MTY3ODkwMTIzNCwiZXhwIjoxOTk0NTY3ODkwfQ.YOUR_SECRET_KEY'

const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY)

async function trySignUp() {
  const testEmail = `testuser${Date.now()}@example.com`
  const testPassword = 'securepassword123'

  console.log(`Attempting to sign up ${testEmail}`)
  const { data, error } = await supabase.auth.signUp({
    email: testEmail,
    password: testPassword
  })

  if (error) {
    console.error('Sign up failed:', error.message)
  } else {
    console.log('Sign up successful! User ID:', data.user.id)
    console.log('Confirmation email sent to:', data.user.email)
  }
}

trySignUp()

Email Confirmation Step

After a user signs up, Supabase usually sends a confirmation email. This is a vital security measure to verify email ownership.

  • Users click a link in the email.
  • This link verifies their email address.
  • Their account becomes active and they can then sign in.

You can configure email templates and redirection URLs in your Supabase project settings.

Logging In Existing Users

Once a user has registered and confirmed their email, they can log in using the signInWithPassword method.

This method authenticates the user and returns a session object, allowing them to access protected resources.

async function signInUser(email, password) {
  const { data, error } = await supabase.auth.signInWithPassword({
    email: email,
    password: password
  })

  if (error) {
    console.error('Sign in error:', error.message)
  } else {
    console.log('User signed in successfully:', data.user.email)
    console.log('Session access token:', data.session.access_token)
  }
}

Try User Sign-In

Here's a runnable example of signing in a user. Remember, for this to work, the user must already be registered and their email confirmed.

You would typically store the session token for subsequent authenticated requests.

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

const SUPABASE_URL = 'https://abcde12345.supabase.co'
const SUPABASE_ANON_KEY = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZSIsInJlZiI6ImFiY2RlMTIzNDUiLCJyb2xlIjoiYW5vbiIsImlhdCI6MTY3ODkwMTIzNCwiZXhwIjoxOTk0NTY3ODkwfQ.YOUR_SECRET_KEY'

const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY)

async function trySignIn() {
  const existingEmail = 'an_existing_user@example.com' // Replace with a real registered email
  const existingPassword = 'securepassword123' // Replace with that user's password

  console.log(`Attempting to sign in ${existingEmail}`)
  const { data, error } = await supabase.auth.signInWithPassword({
    email: existingEmail,
    password: existingPassword
  })

  if (error) {
    console.error('Sign in failed:', error.message)
  } else {
    console.log('Sign in successful! User ID:', data.user.id)
    console.log('Current session:', data.session)
  }
}

trySignIn()

Initiating Password Resets

What if a user forgets their password? Supabase makes it easy to handle password resets securely using resetPasswordForEmail.

This method sends a special magic link to the user's email, which they can use to set a new password.

async function requestPasswordReset(email) {
  const { data, error } = await supabase.auth.resetPasswordForEmail(email, {
    redirectTo: 'https://example.com/update-password' // User redirected here after clicking link
  })

  if (error) {
    console.error('Password reset request error:', error.message)
  } else {
    console.log('Password reset email sent successfully to:', email)
  }
}

Auth Methods Check

Which Supabase Auth method is used to create a new user account with an email and password?

Email/Password Auth Summary

Great job! You've learned the core of email and password authentication with Supabase:

  • Initializing the Supabase client.
  • Using signUp to register new users.
  • Understanding the email confirmation process.
  • Using signInWithPassword to log in existing users.
  • Initiating password resets with resetPasswordForEmail.

This forms the foundation for secure user management in your applications!

Frequently asked questions

Is the “User Registration with Email/Password” lesson free?

Yes — the full text of “User Registration with Email/Password” is free to read here on the web, and the Supabase Backend as a Service course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Supabase Backend as a Service course, upgrade to CoddyKit PRO.

What will I learn in “User Registration with Email/Password”?

Implement standard email and password authentication, including user sign-up, sign-in, and password reset functionalities. You practise Supabase Backend as a Service with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Supabase Backend as a Service?

No prior experience is required. Supabase Backend as a Service on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “User Registration with Email/Password” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Supabase Backend as a Service lesson?

Yes. Every Supabase Backend as a Service lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. User Registration with Email/Password
  2. Social Logins (OAuth Providers)
  3. Managing User Sessions & Profiles
  4. Password Reset and Magic Link Authentication
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