title	description	tocVideo
Build a User Management App with Expo React Native	Learn how to use Supabase in your React Native App.	AE7dKIKMJy4

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

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:

npx create-expo-app -t expo-template-blank-typescript expo-user-management

cd expo-user-management

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

npx expo install @supabase/supabase-js @react-native-async-storage/async-storage @rneui/themed

Now let's create a helper file to initialize the Supabase client. We need the API URL and the 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.

<Tabs scrollable size="large" type="underlined" defaultActiveId="async-storage" queryGroup="auth-store"

```ts lib/supabase.ts
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,
  },
})
```

If you wish to encrypt the user's session information, you can use `aes-js` and store the encryption key in [Expo SecureStore](https://docs.expo.dev/versions/latest/sdk/securestore). The [`aes-js` library](https://github.com/ricmoo/aes-js) is a reputable JavaScript-only implementation of the AES encryption algorithm in CTR mode. A new 256-bit encryption key is generated using the `react-native-get-random-values` library. This key is stored inside Expo's SecureStore, while the value is encrypted and placed inside AsyncStorage.

Please make sure that:
- You keep the `expo-secure-storage`, `aes-js` and `react-native-get-random-values` libraries up-to-date.
- Choose the correct [`SecureStoreOptions`](https://docs.expo.dev/versions/latest/sdk/securestore/#securestoreoptions) for your app's needs. E.g. [`SecureStore.WHEN_UNLOCKED`](https://docs.expo.dev/versions/latest/sdk/securestore/#securestorewhen_unlocked) regulates when the data can be accessed.
- Carefully consider optimizations or other modifications to the above example, as those can lead to introducing subtle security vulnerabilities.

Install the necessary dependencies in the root of your Expo project:

```bash
npm install @supabase/supabase-js
npm install @rneui/themed @react-native-async-storage/async-storage
npm install aes-js react-native-get-random-values
npx expo install expo-secure-store
```

Implement a `LargeSecureStore` class to pass in as Auth storage for the `supabase-js` client:

```ts lib/supabase.ts
import { createClient } from "@supabase/supabase-js";
import AsyncStorage from "@react-native-async-storage/async-storage";
import * as SecureStore from 'expo-secure-store';
import * as aesjs from 'aes-js';
import 'react-native-get-random-values';

// As Expo's SecureStore does not support values larger than 2048
// bytes, an AES-256 key is generated and stored in SecureStore, while
// it is used to encrypt/decrypt values stored in AsyncStorage.
class LargeSecureStore {
  private async _encrypt(key: string, value: string) {
    const encryptionKey = crypto.getRandomValues(new Uint8Array(256 / 8));

    const cipher = new aesjs.ModeOfOperation.ctr(encryptionKey, new aesjs.Counter(1));
    const encryptedBytes = cipher.encrypt(aesjs.utils.utf8.toBytes(value));

    await SecureStore.setItemAsync(key, aesjs.utils.hex.fromBytes(encryptionKey));

    return aesjs.utils.hex.fromBytes(encryptedBytes);
  }

  private async _decrypt(key: string, value: string) {
    const encryptionKeyHex = await SecureStore.getItemAsync(key);
    if (!encryptionKeyHex) {
      return encryptionKeyHex;
    }

    const cipher = new aesjs.ModeOfOperation.ctr(aesjs.utils.hex.toBytes(encryptionKeyHex), new aesjs.Counter(1));
    const decryptedBytes = cipher.decrypt(aesjs.utils.hex.toBytes(value));

    return aesjs.utils.utf8.fromBytes(decryptedBytes);
  }

  async getItem(key: string) {
    const encrypted = await AsyncStorage.getItem(key);
    if (!encrypted) { return encrypted; }

    return await this._decrypt(key, encrypted);
  }

  async removeItem(key: string) {
    await AsyncStorage.removeItem(key);
    await SecureStore.deleteItemAsync(key);
  }

  async setItem(key: string, value: string) {
    const encrypted = await this._encrypt(key, value);

    await AsyncStorage.setItem(key, encrypted);
  }
}

const supabaseUrl = YOUR_REACT_NATIVE_SUPABASE_URL
const supabaseAnonKey = YOUR_REACT_NATIVE_SUPABASE_ANON_KEY

const supabase = createClient(supabaseUrl, supabaseAnonKey, {
  auth: {
    storage: new LargeSecureStore(),
    autoRefreshToken: true,
    persistSession: true,
    detectSessionInUrl: false,
  },
});
```

Set up a login component

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.

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

// 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()
  }
})

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,
  },
})

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.

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

export default function Account({ session }: { session: Session }) {
  const [loading, setLoading] = useState(true)
  const [username, setUsername] = useState('')
  const [website, setWebsite] = useState('')
  const [avatarUrl, setAvatarUrl] = useState('')

  useEffect(() => {
    if (session) getProfile()
  }, [session])

  async function getProfile() {
    try {
      setLoading(true)
      if (!session?.user) throw new Error('No user on the session!')

      const { data, error, status } = await supabase
        .from('profiles')
        .select(`username, website, avatar_url`)
        .eq('id', session?.user.id)
        .single()
      if (error && status !== 406) {
        throw error
      }

      if (data) {
        setUsername(data.username)
        setWebsite(data.website)
        setAvatarUrl(data.avatar_url)
      }
    } catch (error) {
      if (error instanceof Error) {
        Alert.alert(error.message)
      }
    } finally {
      setLoading(false)
    }
  }

  async function updateProfile({
    username,
    website,
    avatar_url,
  }: {
    username: string
    website: string
    avatar_url: string
  }) {
    try {
      setLoading(true)
      if (!session?.user) throw new Error('No user on the session!')

      const updates = {
        id: session?.user.id,
        username,
        website,
        avatar_url,
        updated_at: new Date(),
      }

      const { error } = await supabase.from('profiles').upsert(updates)

      if (error) {
        throw error
      }
    } catch (error) {
      if (error instanceof Error) {
        Alert.alert(error.message)
      }
    } finally {
      setLoading(false)
    }
  }

  return (
    <View style={styles.container}>
      <View style={[styles.verticallySpaced, styles.mt20]}>
        <Input label="Email" value={session?.user?.email} disabled />
      </View>
      <View style={styles.verticallySpaced}>
        <Input label="Username" value={username || ''} onChangeText={(text) => setUsername(text)} />
      </View>
      <View style={styles.verticallySpaced}>
        <Input label="Website" value={website || ''} onChangeText={(text) => setWebsite(text)} />
      </View>

      <View style={[styles.verticallySpaced, styles.mt20]}>
        <Button
          title={loading ? 'Loading ...' : 'Update'}
          onPress={() => updateProfile({ username, website, avatar_url: avatarUrl })}
          disabled={loading}
        />
      </View>

      <View style={styles.verticallySpaced}>
        <Button title="Sign Out" onPress={() => supabase.auth.signOut()} />
      </View>
    </View>
  )
}

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

Launch!

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

import { useState, useEffect } from 'react'
import { supabase } from './lib/supabase'
import Auth from './components/Auth'
import Account from './components/Account'
import { View } 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>
      {session && session.user ? <Account key={session.user.id} session={session} /> : <Auth />}
    </View>
  )
}

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

npm 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.

npx expo install expo-image-picker

Create an upload widget

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

{/* */}

import { useState, useEffect } from 'react'
import { supabase } from '../lib/supabase'
import { StyleSheet, View, Alert, Image, Button } from 'react-native'
import * as ImagePicker from 'expo-image-picker'

interface Props {
  size: number
  url: string | null
  onUpload: (filePath: string) => void
}

export default function Avatar({ url, size = 150, onUpload }: Props) {
  const [uploading, setUploading] = useState(false)
  const [avatarUrl, setAvatarUrl] = useState<string | null>(null)
  const avatarSize = { height: size, width: size }

  useEffect(() => {
    if (url) downloadImage(url)
  }, [url])

  async function downloadImage(path: string) {
    try {
      const { data, error } = await supabase.storage.from('avatars').download(path)

      if (error) {
        throw error
      }

      const fr = new FileReader()
      fr.readAsDataURL(data)
      fr.onload = () => {
        setAvatarUrl(fr.result as string)
      }
    } catch (error) {
      if (error instanceof Error) {
        console.log('Error downloading image: ', error.message)
      }
    }
  }

  async function uploadAvatar() {
    try {
      setUploading(true)

      const result = await ImagePicker.launchImageLibraryAsync({
        mediaTypes: ImagePicker.MediaTypeOptions.Images, // Restrict to only images
        allowsMultipleSelection: false, // Can only select one image
        allowsEditing: true, // Allows the user to crop / rotate their photo before uploading it
        quality: 1,
        exif: false, // We don't want nor need that data.
      })

      if (result.canceled || !result.assets || result.assets.length === 0) {
        console.log('User cancelled image picker.')
        return
      }

      const image = result.assets[0]
      console.log('Got image', image)

      if (!image.uri) {
        throw new Error('No image uri!') // Realistically, this should never happen, but just in case...
      }

      const arraybuffer = await fetch(image.uri).then((res) => res.arrayBuffer())

      const fileExt = image.uri?.split('.').pop()?.toLowerCase() ?? 'jpeg'
      const path = `${Date.now()}.${fileExt}`
      const { data, error: uploadError } = await supabase.storage
        .from('avatars')
        .upload(path, arraybuffer, {
          contentType: image.mimeType ?? 'image/jpeg',
        })

      if (uploadError) {
        throw uploadError
      }

      onUpload(data.path)
    } catch (error) {
      if (error instanceof Error) {
        Alert.alert(error.message)
      } else {
        throw error
      }
    } finally {
      setUploading(false)
    }
  }

  return (
    <View>
      {avatarUrl ? (
        <Image
          source={{ uri: avatarUrl }}
          accessibilityLabel="Avatar"
          style={[avatarSize, styles.avatar, styles.image]}
        />
      ) : (
        <View style={[avatarSize, styles.avatar, styles.noImage]} />
      )}
      <View>
        <Button
          title={uploading ? 'Uploading ...' : 'Upload'}
          onPress={uploadAvatar}
          disabled={uploading}
        />
      </View>
    </View>
  )
}

const styles = StyleSheet.create({
  avatar: {
    borderRadius: 5,
    overflow: 'hidden',
    maxWidth: '100%',
  },
  image: {
    objectFit: 'cover',
    paddingTop: 0,
  },
  noImage: {
    backgroundColor: '#333',
    borderWidth: 1,
    borderStyle: 'solid',
    borderColor: 'rgb(200, 200, 200)',
    borderRadius: 5,
  },
})

{/* */}

Add the new widget

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

// Import the new component
import Avatar from './Avatar'

// ...
return (
  <View>
    {/* Add to the body */}
    <View>
      <Avatar
        size={200}
        url={avatarUrl}
        onUpload={(url: string) => {
          setAvatarUrl(url)
          updateProfile({ username, website, avatar_url: url })
        }}
      />
    </View>
    {/* ... */}
  </View>
)
// ...

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

npx expo prebuild

At this stage you have a fully functional application!

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with-expo-react-native.mdx

with-expo-react-native.mdx

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

Files

with-expo-react-native.mdx

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History

with-expo-react-native.mdx

File metadata and controls

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