Use Supabase Auth with React Native

Learn how to use Supabase Auth with React Native

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

 select * from auth.users;

Create a React app

Create a React app using the create-expo-app command.

Terminal

npx create-expo-app -t expo-template-blank-typescript my-app

Install the Supabase client library

Install supabase-js and the required dependencies.

Terminal

cd my-app && npx expo install @supabase/supabase-js @react-native-async-storage/async-storage @rneui/themed react-native-url-polyfill

Set up your login component

Create a helper file lib/supabase.ts that exports a Supabase client using your Project URL and public API (anon) key.

lib/supabase.ts

import { AppState } from 'react-native'
import 'react-native-url-polyfill/auto'
import AsyncStorage from '@react-native-async-storage/async-storage'
import { createClient } from '@supabase/supabase-js'

const supabaseUrl = YOUR_REACT_NATIVE_SUPABASE_URL
const supabaseAnonKey = YOUR_REACT_NATIVE_SUPABASE_ANON_KEY

export const supabase = createClient(supabaseUrl, supabaseAnonKey, {
  auth: {
    storage: AsyncStorage,
    autoRefreshToken: true,
    persistSession: true,
    detectSessionInUrl: false,
  },
})

// Tells Supabase Auth to continuously refresh the session automatically
// if the app is in the foreground. When this is added, you will continue
// to receive `onAuthStateChange` events with the `TOKEN_REFRESHED` or
// `SIGNED_OUT` event if the user's session is terminated. This should
// only be registered once.
AppState.addEventListener('change', (state) => {
  if (state === 'active') {
    supabase.auth.startAutoRefresh()
  } else {
    supabase.auth.stopAutoRefresh()
  }
})

Create a login component

Let's set up a React Native component to manage logins and sign ups.

components/Auth.tsx

import React, { useState } from 'react'
import { Alert, StyleSheet, View } from 'react-native'
import { supabase } from '../lib/supabase'
import { Button, Input } from '@rneui/themed'

export default function Auth() {
  const [email, setEmail] = useState('')
  const [password, setPassword] = useState('')
  const [loading, setLoading] = useState(false)

  async function signInWithEmail() {
    setLoading(true)
    const { error } = await supabase.auth.signInWithPassword({
      email: email,
      password: password,
    })

    if (error) Alert.alert(error.message)
    setLoading(false)
  }

  async function signUpWithEmail() {
    setLoading(true)
    const {
      data: { session },
      error,
    } = await supabase.auth.signUp({
      email: email,
      password: password,
    })

    if (error) Alert.alert(error.message)
    if (!session) Alert.alert('Please check your inbox for email verification!')
    setLoading(false)
  }

  return (
    <View style={styles.container}>
      <View style={[styles.verticallySpaced, styles.mt20]}>
        <Input
          label="Email"
          leftIcon={{ type: 'font-awesome', name: 'envelope' }}
          onChangeText={(text) => setEmail(text)}
          value={email}
          placeholder="email@address.com"
          autoCapitalize={'none'}
        />
      </View>
      <View style={styles.verticallySpaced}>
        <Input
          label="Password"
          leftIcon={{ type: 'font-awesome', name: 'lock' }}
          onChangeText={(text) => setPassword(text)}
          value={password}
          secureTextEntry={true}
          placeholder="Password"
          autoCapitalize={'none'}
        />
      </View>
      <View style={[styles.verticallySpaced, styles.mt20]}>
        <Button title="Sign in" disabled={loading} onPress={() => signInWithEmail()} />
      </View>
      <View style={styles.verticallySpaced}>
        <Button title="Sign up" disabled={loading} onPress={() => signUpWithEmail()} />
      </View>
    </View>
  )
}

const styles = StyleSheet.create({
  container: {
    marginTop: 40,
    padding: 12,
  },
  verticallySpaced: {
    paddingTop: 4,
    paddingBottom: 4,
    alignSelf: 'stretch',
  },
  mt20: {
    marginTop: 20,
  },
})

Add the Auth component to your app

Add the Auth component to your App.tsx file. If the user is logged in, print the user id to the screen.

App.tsx

import 'react-native-url-polyfill/auto'
import { useState, useEffect } from 'react'
import { supabase } from './lib/supabase'
import Auth from './components/Auth'
import Account from './components/Account'
import { View, Text } from 'react-native'
import { Session } from '@supabase/supabase-js'

export default function App() {
  const [session, setSession] = useState<Session | null>(null)

  useEffect(() => {
    supabase.auth.getSession().then(({ data: { session } }) => {
      setSession(session)
    })

    supabase.auth.onAuthStateChange((_event, session) => {
      setSession(session)
    })
  }, [])

  return (
    <View>
      <Auth />
      {session && session.user && <Text>{session.user.id}</Text>}
    </View>
  )
}

Start the app

Start the app, and follow the instructions in the terminal.

Terminal

npm start