One of the most fundamental aspects of building modern applications is user authentication. Supabase makes this incredibly straightforward with its client libraries. Whether you're using JavaScript, Python, or any other supported language, you'll find a unified API to handle user sign-up, sign-in, sign-out, and password management. This allows you to quickly implement secure user flows without reinventing the wheel.
Let's explore how you can authenticate users using the Supabase JavaScript client library. We'll cover the most common scenarios.
Before you can authenticate, you need to initialize the Supabase client. Make sure you have your Supabase URL and anon public key handy. You can find these in your Supabase project settings under the 'API' section.
import { createClient } from '@supabase/supabase-js'
const supabaseUrl = 'YOUR_SUPABASE_URL'
const supabaseAnonKey = 'YOUR_SUPABASE_ANON_KEY'
export const supabase = createClient(supabaseUrl, supabaseAnonKey)Signing up a new user is as simple as calling the signUp method. This method takes an email and password, and optionally, user metadata. Supabase will handle sending a confirmation email (if configured) and creating the user record in your auth.users table.
async function signUpNewUser() {
const { data, error } = await supabase.auth.signUp({
email: 'example@email.com',
password: 'your-secure-password',
})
if (error) {
console.error('Error signing up:', error.message)
} else {
console.log('Sign up successful! Please check your email for verification.', data)
}
}For users who already have an account, the signInWithPassword method is your go-to. Similar to sign-up, it requires an email and password.
async function signInUser() {
const { data, error } = await supabase.auth.signInWithPassword({
email: 'example@email.com',
password: 'your-secure-password',
})
if (error) {
console.error('Error signing in:', error.message)
} else {
console.log('Sign in successful!', data.user)
}
}