Build a User Management App with Expo React Native

This tutorial demonstrates how to build a basic user management app. The app authenticates and identifies the user, stores their profile information in the database, and allows the user to log in, update their profile details, and upload a profile photo. The app uses:

Supabase Database - a Postgres database for storing your user data and Row Level Security so data is protected and users can only access their own information.
Supabase Auth - users log in through magic links sent to their email (without having to set up passwords).
Supabase Storage - users can upload a profile photo.

Supabase User Management example

If you get stuck while working through this guide, refer to the full example on GitHub.

Project setup

Before we start building we're going to set up our Database and API. This is as simple as starting a new Project in Supabase and then creating a "schema" inside the database.

Create a project

Create a new project in the Supabase Dashboard.
Enter your project details.
Wait for the new database to launch.

Set up the database schema

Now we are going to set up the database schema. We can use the "User Management Starter" quickstart in the SQL Editor, or you can just copy/paste the SQL from below and run it yourself.

Go to the SQL Editor page in the Dashboard.
Click User Management Starter.
Click Run.

You can easily pull the database schema down to your local project by running the db pull command. Read the local development docs for detailed instructions.


_10supabase link --project-ref <project-id>
_10# You can get <project-id> from your project's dashboard URL: https://supabase.com/dashboard/project/<project-id>
_10supabase db pull

Get the API Keys

Now that you've created some database tables, you are ready to insert data using the auto-generated API. We just need to get the Project URL and anon key from the API settings.

Go to the API Settings page in the Dashboard.
Find your Project URL, anon, and service_role keys on this page.

Building the app

Let's start building the React Native app from scratch.

Initialize a React Native app

We can use expo to initialize an app called expo-user-management:


_10npx create-expo-app -t expo-template-blank-typescript expo-user-management
_10
_10cd expo-user-management

Then let's install the additional dependencies: supabase-js


_10npx expo install @supabase/supabase-js @react-native-async-storage/async-storage react-native-elements react-native-url-polyfill

Now let's create a helper file to initialize the Supabase client. We need the API URL and the anon key that you copied earlier. These variables are safe to expose in your Expo app since Supabase has Row Level Security enabled on your Database.

lib/supabase.ts


_15import 'react-native-url-polyfill/auto'
_15import AsyncStorage from '@react-native-async-storage/async-storage'
_15import { createClient } from '@supabase/supabase-js'
_15
_15const supabaseUrl = YOUR_REACT_NATIVE_SUPABASE_URL
_15const supabaseAnonKey = YOUR_REACT_NATIVE_SUPABASE_ANON_KEY
_15
_15export const supabase = createClient(supabaseUrl, supabaseAnonKey, {
_15  auth: {
_15    storage: AsyncStorage,
_15    autoRefreshToken: true,
_15    persistSession: true,
_15    detectSessionInUrl: false,
_15  },
_15})

Let's set up a React Native component to manage logins and sign ups. Users would be able to sign in with their email and password.

components/Auth.tsx


_95import React, { useState } from 'react'
_95import { Alert, StyleSheet, View, AppState } from 'react-native'
_95import { supabase } from '../lib/supabase'
_95import { Button, Input } from 'react-native-elements'
_95
_95// Tells Supabase Auth to continuously refresh the session automatically if
_95// the app is in the foreground. When this is added, you will continue to receive
_95// `onAuthStateChange` events with the `TOKEN_REFRESHED` or `SIGNED_OUT` event
_95// if the user's session is terminated. This should only be registered once.
_95AppState.addEventListener('change', (state) => {
_95  if (state === 'active') {
_95    supabase.auth.startAutoRefresh()
_95  } else {
_95    supabase.auth.stopAutoRefresh()
_95  }
_95})
_95
_95export default function Auth() {
_95  const [email, setEmail] = useState('')
_95  const [password, setPassword] = useState('')
_95  const [loading, setLoading] = useState(false)
_95
_95  async function signInWithEmail() {
_95    setLoading(true)
_95    const { error } = await supabase.auth.signInWithPassword({
_95      email: email,
_95      password: password,
_95    })
_95
_95    if (error) Alert.alert(error.message)
_95    setLoading(false)
_95  }
_95
_95  async function signUpWithEmail() {
_95    setLoading(true)
_95    const {
_95      data: { session },
_95      error,
_95    } = await supabase.auth.signUp({
_95      email: email,
_95      password: password,
_95    })
_95
_95    if (error) Alert.alert(error.message)
_95    if (!session) Alert.alert('Please check your inbox for email verification!')
_95    setLoading(false)
_95  }
_95
_95  return (
_95    <View style={styles.container}>
_95      <View style={[styles.verticallySpaced, styles.mt20]}>
_95        <Input
_95          label="Email"
_95          leftIcon={{ type: 'font-awesome', name: 'envelope' }}
_95          onChangeText={(text) => setEmail(text)}
_95          value={email}
_95          placeholder="email@address.com"
_95          autoCapitalize={'none'}
_95        />
_95      </View>
_95      <View style={styles.verticallySpaced}>
_95        <Input
_95          label="Password"
_95          leftIcon={{ type: 'font-awesome', name: 'lock' }}
_95          onChangeText={(text) => setPassword(text)}
_95          value={password}
_95          secureTextEntry={true}
_95          placeholder="Password"
_95          autoCapitalize={'none'}
_95        />
_95      </View>
_95      <View style={[styles.verticallySpaced, styles.mt20]}>
_95        <Button title="Sign in" disabled={loading} onPress={() => signInWithEmail()} />
_95      </View>
_95      <View style={styles.verticallySpaced}>
_95        <Button title="Sign up" disabled={loading} onPress={() => signUpWithEmail()} />
_95      </View>
_95    </View>
_95  )
_95}
_95
_95const styles = StyleSheet.create({
_95  container: {
_95    marginTop: 40,
_95    padding: 12,
_95  },
_95  verticallySpaced: {
_95    paddingTop: 4,
_95    paddingBottom: 4,
_95    alignSelf: 'stretch',
_95  },
_95  mt20: {
_95    marginTop: 20,
_95  },
_95})

By default Supabase Auth requires email verification before a session is created for the users. To support email verification you need to implement deep link handling!

While testing, you can disable email confirmation in your project's email auth provider settings.

Account page

After a user is signed in we can allow them to edit their profile details and manage their account.

Let's create a new component for that called Account.tsx.

components/Account.tsx


_120import { useState, useEffect } from 'react'
_120import { supabase } from '../lib/supabase'
_120import { StyleSheet, View, Alert } from 'react-native'
_120import { Button, Input } from 'react-native-elements'
_120import { Session } from '@supabase/supabase-js'
_120
_120export default function Account({ session }: { session: Session }) {
_120  const [loading, setLoading] = useState(true)
_120  const [username, setUsername] = useState('')
_120  const [website, setWebsite] = useState('')
_120  const [avatarUrl, setAvatarUrl] = useState('')
_120
_120  useEffect(() => {
_120    if (session) getProfile()
_120  }, [session])
_120
_120  async function getProfile() {
_120    try {
_120      setLoading(true)
_120      if (!session?.user) throw new Error('No user on the session!')
_120
_120      const { data, error, status } = await supabase
_120        .from('profiles')
_120        .select(`username, website, avatar_url`)
_120        .eq('id', session?.user.id)
_120        .single()
_120      if (error && status !== 406) {
_120        throw error
_120      }
_120
_120      if (data) {
_120        setUsername(data.username)
_120        setWebsite(data.website)
_120        setAvatarUrl(data.avatar_url)
_120      }
_120    } catch (error) {
_120      if (error instanceof Error) {
_120        Alert.alert(error.message)
_120      }
_120    } finally {
_120      setLoading(false)
_120    }
_120  }
_120
_120  async function updateProfile({
_120    username,
_120    website,
_120    avatar_url,
_120  }: {
_120    username: string
_120    website: string
_120    avatar_url: string
_120  }) {
_120    try {
_120      setLoading(true)
_120      if (!session?.user) throw new Error('No user on the session!')
_120
_120      const updates = {
_120        id: session?.user.id,
_120        username,
_120        website,
_120        avatar_url,
_120        updated_at: new Date(),
_120      }
_120
_120      const { error } = await supabase.from('profiles').upsert(updates)
_120
_120      if (error) {
_120        throw error
_120      }
_120    } catch (error) {
_120      if (error instanceof Error) {
_120        Alert.alert(error.message)
_120      }
_120    } finally {
_120      setLoading(false)
_120    }
_120  }
_120
_120  return (
_120    <View style={styles.container}>
_120      <View style={[styles.verticallySpaced, styles.mt20]}>
_120        <Input label="Email" value={session?.user?.email} disabled />
_120      </View>
_120      <View style={styles.verticallySpaced}>
_120        <Input label="Username" value={username || ''} onChangeText={(text) => setUsername(text)} />
_120      </View>
_120      <View style={styles.verticallySpaced}>
_120        <Input label="Website" value={website || ''} onChangeText={(text) => setWebsite(text)} />
_120      </View>
_120
_120      <View style={[styles.verticallySpaced, styles.mt20]}>
_120        <Button
_120          title={loading ? 'Loading ...' : 'Update'}
_120          onPress={() => updateProfile({ username, website, avatar_url: avatarUrl })}
_120          disabled={loading}
_120        />
_120      </View>
_120
_120      <View style={styles.verticallySpaced}>
_120        <Button title="Sign Out" onPress={() => supabase.auth.signOut()} />
_120      </View>
_120    </View>
_120  )
_120}
_120
_120const styles = StyleSheet.create({
_120  container: {
_120    marginTop: 40,
_120    padding: 12,
_120  },
_120  verticallySpaced: {
_120    paddingTop: 4,
_120    paddingBottom: 4,
_120    alignSelf: 'stretch',
_120  },
_120  mt20: {
_120    marginTop: 20,
_120  },
_120})

Launch!

Now that we have all the components in place, let's update App.tsx:

App.tsx


_27import 'react-native-url-polyfill/auto'
_27import { useState, useEffect } from 'react'
_27import { supabase } from './lib/supabase'
_27import Auth from './components/Auth'
_27import Account from './components/Account'
_27import { View } from 'react-native'
_27import { Session } from '@supabase/supabase-js'
_27
_27export default function App() {
_27  const [session, setSession] = useState<Session | null>(null)
_27
_27  useEffect(() => {
_27    supabase.auth.getSession().then(({ data: { session } }) => {
_27      setSession(session)
_27    })
_27
_27    supabase.auth.onAuthStateChange((_event, session) => {
_27      setSession(session)
_27    })
_27  }, [])
_27
_27  return (
_27    <View>
_27      {session && session.user ? <Account key={session.user.id} session={session} /> : <Auth />}
_27    </View>
_27  )
_27}

Once that's done, run this in a terminal window:


_10npm start

And then press the appropriate key for the environment you want to test the app in and you should see the completed app.

Bonus: Profile photos

Every Supabase project is configured with Storage for managing large files like photos and videos.

Additional dependency installation

You will need an image picker that works on the environment you will build the project for, we will use expo-image-picker in this example.


_10expo install expo-image-picker

Let's create an avatar for the user so that they can upload a profile photo. We can start by creating a new component:

components/Avatar.tsx


_130import { useState, useEffect } from 'react'
_130import { supabase } from '../lib/supabase'
_130import { StyleSheet, View, Alert, Image, Button } from 'react-native'
_130import * as ImagePicker from 'expo-image-picker'
_130
_130interface Props {
_130  size: number
_130  url: string | null
_130  onUpload: (filePath: string) => void
_130}
_130
_130export default function Avatar({ url, size = 150, onUpload }: Props) {
_130  const [uploading, setUploading] = useState(false)
_130  const [avatarUrl, setAvatarUrl] = useState<string | null>(null)
_130  const avatarSize = { height: size, width: size }
_130
_130  useEffect(() => {
_130    if (url) downloadImage(url)
_130  }, [url])
_130
_130  async function downloadImage(path: string) {
_130    try {
_130      const { data, error } = await supabase.storage.from('avatars').download(path)
_130
_130      if (error) {
_130        throw error
_130      }
_130
_130      const fr = new FileReader()
_130      fr.readAsDataURL(data)
_130      fr.onload = () => {
_130        setAvatarUrl(fr.result as string)
_130      }
_130    } catch (error) {
_130      if (error instanceof Error) {
_130        console.log('Error downloading image: ', error.message)
_130      }
_130    }
_130  }
_130
_130  async function uploadAvatar() {
_130    try {
_130      setUploading(true)
_130
_130      const result = await ImagePicker.launchImageLibraryAsync({
_130        mediaTypes: ImagePicker.MediaTypeOptions.Images, // Restrict to only images
_130        allowsMultipleSelection: false, // Can only select one image
_130        allowsEditing: true, // Allows the user to crop / rotate their photo before uploading it
_130        quality: 1,
_130        exif: false, // We don't want nor need that data.
_130      })
_130
_130      if (result.canceled || !result.assets || result.assets.length === 0) {
_130        console.log('User cancelled image picker.')
_130        return
_130      }
_130
_130      const image = result.assets[0]
_130      console.log('Got image', image)
_130
_130      if (!image.uri) {
_130        throw new Error('No image uri!') // Realistically, this should never happen, but just in case...
_130      }
_130
_130      const arraybuffer = await fetch(image.uri).then((res) => res.arrayBuffer())
_130
_130      const fileExt = image.uri?.split('.').pop()?.toLowerCase() ?? 'jpeg'
_130      const path = `${Date.now()}.${fileExt}`
_130      const { data, error: uploadError } = await supabase.storage
_130        .from('avatars')
_130        .upload(path, arraybuffer, {
_130          contentType: image.mimeType ?? 'image/jpeg',
_130        })
_130
_130      if (uploadError) {
_130        throw uploadError
_130      }
_130
_130      onUpload(data.path)
_130    } catch (error) {
_130      if (error instanceof Error) {
_130        Alert.alert(error.message)
_130      } else {
_130        throw error
_130      }
_130    } finally {
_130      setUploading(false)
_130    }
_130  }
_130
_130  return (
_130    <View>
_130      {avatarUrl ? (
_130        <Image
_130          source={{ uri: avatarUrl }}
_130          accessibilityLabel="Avatar"
_130          style={[avatarSize, styles.avatar, styles.image]}
_130        />
_130      ) : (
_130        <View style={[avatarSize, styles.avatar, styles.noImage]} />
_130      )}
_130      <View>
_130        <Button
_130          title={uploading ? 'Uploading ...' : 'Upload'}
_130          onPress={uploadAvatar}
_130          disabled={uploading}
_130        />
_130      </View>
_130    </View>
_130  )
_130}
_130
_130const styles = StyleSheet.create({
_130  avatar: {
_130    borderRadius: 5,
_130    overflow: 'hidden',
_130    maxWidth: '100%',
_130  },
_130  image: {
_130    objectFit: 'cover',
_130    paddingTop: 0,
_130  },
_130  noImage: {
_130    backgroundColor: '#333',
_130    borderWidth: 1,
_130    borderStyle: 'solid',
_130    borderColor: 'rgb(200, 200, 200)',
_130    borderRadius: 5,
_130  },
_130})

And then we can add the widget to the Account page:

components/Account.tsx


_21// Import the new component
_21import Avatar from './Avatar'
_21
_21// ...
_21return (
_21  <View>
_21    {/* Add to the body */}
_21    <View>
_21      <Avatar
_21        size={200}
_21        url={avatarUrl}
_21        onUpload={(url: string) => {
_21          setAvatarUrl(url)
_21          updateProfile({ username, website, avatar_url: url })
_21        }}
_21      />
_21    </View>
_21    {/* ... */}
_21  </View>
_21)
_21// ...

Now you will need to run the prebuild command to get the application working on your chosen platform.


_10expo prebuild

Storage management

If you upload additional profile photos, they'll accumulate in the avatars bucket because of their random names with only the latest being referenced from public.profiles and the older versions getting orphaned.

To automatically remove obsolete storage objects, extend the database triggers. Note that it is not sufficient to delete the objects from the storage.objects table because that would orphan and leak the actual storage objects in the S3 backend. Instead, invoke the storage API within Postgres via the http extension.

Enable the http extension for the extensions schema in the Dashboard. Then, define the following SQL functions in the SQL Editor to delete storage objects via the API:


_34create or replace function delete_storage_object(bucket text, object text, out status int, out content text)
_34returns record
_34language 'plpgsql'
_34security definer
_34as $$
_34declare
_34  project_url text := '<YOURPROJECTURL>';
_34  service_role_key text := '<YOURSERVICEROLEKEY>'; --  full access needed
_34  url text := project_url||'/storage/v1/object/'||bucket||'/'||object;
_34begin
_34  select
_34      into status, content
_34           result.status::int, result.content::text
_34      FROM extensions.http((
_34    'DELETE',
_34    url,
_34    ARRAY[extensions.http_header('authorization','Bearer '||service_role_key)],
_34    NULL,
_34    NULL)::extensions.http_request) as result;
_34end;
_34$$;
_34
_34create or replace function delete_avatar(avatar_url text, out status int, out content text)
_34returns record
_34language 'plpgsql'
_34security definer
_34as $$
_34begin
_34  select
_34      into status, content
_34           result.status, result.content
_34      from public.delete_storage_object('avatars', avatar_url) as result;
_34end;
_34$$;

Next, add a trigger that removes any obsolete avatar whenever the profile is updated or deleted:


_32create or replace function delete_old_avatar()
_32returns trigger
_32language 'plpgsql'
_32security definer
_32as $$
_32declare
_32  status int;
_32  content text;
_32  avatar_name text;
_32begin
_32  if coalesce(old.avatar_url, '') <> ''
_32      and (tg_op = 'DELETE' or (old.avatar_url <> coalesce(new.avatar_url, ''))) then
_32    -- extract avatar name
_32    avatar_name := old.avatar_url;
_32    select
_32      into status, content
_32      result.status, result.content
_32      from public.delete_avatar(avatar_name) as result;
_32    if status <> 200 then
_32      raise warning 'Could not delete avatar: % %', status, content;
_32    end if;
_32  end if;
_32  if tg_op = 'DELETE' then
_32    return old;
_32  end if;
_32  return new;
_32end;
_32$$;
_32
_32create trigger before_profile_changes
_32  before update of avatar_url or delete on public.profiles
_32  for each row execute function public.delete_old_avatar();

Finally, delete the public.profile row before a user is deleted. If this step is omitted, you won't be able to delete users without first manually deleting their avatar image.


_14create or replace function delete_old_profile()
_14returns trigger
_14language 'plpgsql'
_14security definer
_14as $$
_14begin
_14  delete from public.profiles where id = old.id;
_14  return old;
_14end;
_14$$;
_14
_14create trigger before_delete_user
_14  before delete on auth.users
_14  for each row execute function public.delete_old_profile();

At this stage you have a fully functional application!

Edit this page on GitHub

Product

Data API

Development Cycle

Client Library Reference

Resources

Build a User Management App with Expo React Native

Project setup

Create a project

Set up the database schema

Get the API Keys

Building the app

Initialize a React Native app

Account page

Launch!

Bonus: Profile photos

Additional dependency installation

Create an upload widget

Add the new widget

Storage management

Build a User Management App with Expo React Native

Project setup#

Create a project#

Set up the database schema#

Get the API Keys#

Building the app#

Initialize a React Native app#

Set up a login component#

Account page#

Launch!#

Bonus: Profile photos#

Additional dependency installation#

Create an upload widget#

Add the new widget#

Storage management#

Project setup

Create a project

Set up the database schema

Get the API Keys

Building the app

Initialize a React Native app

Set up a login component

Account page

Launch!

Bonus: Profile photos

Additional dependency installation

Create an upload widget

Add the new widget

Storage management