Build a User Management App with Flutter

<$Partial path="quickstart_intro.mdx" />

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

</Admonition>

<$Partial path="project_setup.mdx" variables={{ "framework": "flutter", "tab": "mobiles" }} />

Building the app

Let's start building the Flutter app from scratch.

Initialize a Flutter app

We can use flutter create to initialize an app called supabase_quickstart:

bash

flutter create supabase_quickstart

Then let's install the only additional dependency: supabase_flutter

Copy and paste the following line in your pubspec.yaml to install the package:

yaml

supabase_flutter: ^2.0.0

Run flutter pub get to install the dependencies.

Setup deep links

Now that we have the dependencies installed let's setup deep links. Setting up deep links is required to bring back the user to the app when they click on the magic link to sign in. We can setup deep links with just a minor tweak on our Flutter application.

We have to use io.supabase.flutterquickstart as the scheme. In this example, we will use login-callback as the host for our deep link, but you can change it to whatever you would like.

First, add io.supabase.flutterquickstart://login-callback/ as a new redirect URL in the Dashboard.

That is it on Supabase's end and the rest are platform specific settings:

<Tabs scrollable size="small" type="underlined" defaultActiveId="ios" queryGroup="platform"

<TabPanel id="ios" label="iOS"> Edit the `ios/Runner/Info.plist` file.

Add CFBundleURLTypes to enable deep linking:

<$CodeTabs>

xml

<!-- ... other tags -->
<plist>
<dict>
  <!-- ... other tags -->

  <!-- Add this array for Deep Links -->
  <key>CFBundleURLTypes</key>
  <array>
    <dict>
      <key>CFBundleTypeRole</key>
      <string>Editor</string>
      <key>CFBundleURLSchemes</key>
      <array>
        <string>io.supabase.flutterquickstart</string>
      </array>
    </dict>
  </array>
  <!-- ... other tags -->
</dict>
</plist>

</$CodeTabs>

</TabPanel> <TabPanel id="android" label="Android"> Edit the `android/app/src/main/AndroidManifest.xml` file.

Add an intent-filter to enable deep linking:

<$CodeTabs>

xml

<manifest ...>
  <!-- ... other tags -->
  <application ...>
    <activity ...>
      <!-- ... other tags -->

      <!-- Add this intent-filter for Deep Links -->
      <intent-filter>
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        <!-- Accepts URIs that begin with YOUR_SCHEME://YOUR_HOST -->
        <data
          android:scheme="io.supabase.flutterquickstart"
          android:host="login-callback" />
      </intent-filter>

    </activity>
  </application>
</manifest>

</$CodeTabs>

</TabPanel> <TabPanel id="web" label="Web"> Supabase redirects do not work with Flutter's [default URL strategy](https://docs.flutter.dev/ui/navigation/url-strategies). We can switch to the path URL strategy as follows:

dart

import 'package:flutter_web_plugins/url_strategy.dart';

void main() {
  usePathUrlStrategy();
  runApp(ExampleApp());
}

</TabPanel> </Tabs>

Main function

Now that we have deep links ready let's initialize the Supabase client inside our main function with the API credentials that you copied earlier. These variables will be exposed on the app, and that's completely fine since we have Row Level Security enabled on our Database.

<$CodeTabs>

dart

import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

Future<void> main() async {
  await Supabase.initialize(
    url: 'YOUR_SUPABASE_URL',
    publishableKey: 'YOUR_SUPABASE_PUBLISHABLE_KEY',
  );
  runApp(const MyApp());
}

final supabase = Supabase.instance.client;

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(title: 'Supabase Flutter');
  }
}

extension ContextExtension on BuildContext {
  void showSnackBar(String message, {bool isError = false}) {
    ScaffoldMessenger.of(this).showSnackBar(
      SnackBar(
        content: Text(message),
        backgroundColor: isError
            ? Theme.of(this).colorScheme.error
            : Theme.of(this).snackBarTheme.backgroundColor,
      ),
    );
  }
}

</$CodeTabs>

Notice that we have a showSnackBar extension method that we will use to show snack bars in the app. You could define this method in a separate file and import it where needed, but for simplicity, we will define it here.

Let's create a Flutter widget to manage logins and sign ups. We will use Magic Links, so users can sign in with their email without using passwords.

Notice that this page sets up a listener on the user's auth state using onAuthStateChange. A new event will fire when the user comes back to the app by clicking their magic link, which this page can catch and redirect the user accordingly.

<$CodeTabs>

dart

import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/main.dart';
import 'package:supabase_quickstart/pages/account_page.dart';

class LoginPage extends StatefulWidget {
  const LoginPage({super.key});

  @override
  State<LoginPage> createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginPage> {
  bool _isLoading = false;
  bool _redirecting = false;
  late final TextEditingController _emailController = TextEditingController();
  late final StreamSubscription<AuthState> _authStateSubscription;

  Future<void> _signIn() async {
    try {
      setState(() {
        _isLoading = true;
      });
      await supabase.auth.signInWithOtp(
        email: _emailController.text.trim(),
        emailRedirectTo:
            kIsWeb ? null : 'io.supabase.flutterquickstart://login-callback/',
      );
      if (mounted) {
        context.showSnackBar('Check your email for a login link!');

        _emailController.clear();
      }
    } on AuthException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
      }
    }
  }

  @override
  void initState() {
    _authStateSubscription = supabase.auth.onAuthStateChange.listen(
      (data) {
        if (_redirecting) return;
        final session = data.session;
        if (session != null) {
          _redirecting = true;
          Navigator.of(context).pushReplacement(
            MaterialPageRoute(builder: (context) => const AccountPage()),
          );
        }
      },
      onError: (error) {
        if (error is AuthException) {
          context.showSnackBar(error.message, isError: true);
        } else {
          context.showSnackBar('Unexpected error occurred', isError: true);
        }
      },
    );
    super.initState();
  }

  @override
  void dispose() {
    _emailController.dispose();
    _authStateSubscription.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Sign In')),
      body: ListView(
        padding: const EdgeInsets.symmetric(vertical: 18, horizontal: 12),
        children: [
          const Text('Sign in via the magic link with your email below'),
          const SizedBox(height: 18),
          TextFormField(
            controller: _emailController,
            decoration: const InputDecoration(labelText: 'Email'),
          ),
          const SizedBox(height: 18),
          ElevatedButton(
            onPressed: _isLoading ? null : _signIn,
            child: Text(_isLoading ? 'Sending...' : 'Send Magic Link'),
          ),
        ],
      ),
    );
  }
}

</$CodeTabs>

Set up 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 widget called account_page.dart for that.

<$CodeTabs>

dart

import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/main.dart';
import 'package:supabase_quickstart/pages/login_page.dart';

class AccountPage extends StatefulWidget {
  const AccountPage({super.key});

  @override
  State<AccountPage> createState() => _AccountPageState();
}

class _AccountPageState extends State<AccountPage> {
  final _usernameController = TextEditingController();
  final _websiteController = TextEditingController();

  String? _avatarUrl;
  var _loading = true;

  /// Called once a user id is received within `onAuthenticated()`
  Future<void> _getProfile() async {
    setState(() {
      _loading = true;
    });

    try {
      final userId = supabase.auth.currentSession!.user.id;
      final data =
          await supabase.from('profiles').select().eq('id', userId).single();
      _usernameController.text = (data['username'] ?? '') as String;
      _websiteController.text = (data['website'] ?? '') as String;
      _avatarUrl = (data['avatar_url'] ?? '') as String;
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  /// Called when user taps `Update` button
  Future<void> _updateProfile() async {
    setState(() {
      _loading = true;
    });
    final userName = _usernameController.text.trim();
    final website = _websiteController.text.trim();
    final user = supabase.auth.currentUser;
    final updates = {
      'id': user!.id,
      'username': userName,
      'website': website,
      'updated_at': DateTime.now().toIso8601String(),
    };
    try {
      await supabase.from('profiles').upsert(updates);
      if (mounted) context.showSnackBar('Successfully updated profile!');
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  Future<void> _signOut() async {
    try {
      await supabase.auth.signOut();
    } on AuthException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (_) => const LoginPage()),
        );
      }
    }
  }

  @override
  void initState() {
    super.initState();
    _getProfile();
  }

  @override
  void dispose() {
    _usernameController.dispose();
    _websiteController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Profile')),
      body: ListView(
        padding: const EdgeInsets.symmetric(vertical: 18, horizontal: 12),
        children: [
          TextFormField(
            controller: _usernameController,
            decoration: const InputDecoration(labelText: 'User Name'),
          ),
          const SizedBox(height: 18),
          TextFormField(
            controller: _websiteController,
            decoration: const InputDecoration(labelText: 'Website'),
          ),
          const SizedBox(height: 18),
          ElevatedButton(
            onPressed: _loading ? null : _updateProfile,
            child: Text(_loading ? 'Saving...' : 'Update'),
          ),
          const SizedBox(height: 18),
          TextButton(onPressed: _signOut, child: const Text('Sign Out')),
        ],
      ),
    );
  }
}

</$CodeTabs>

Launch!

Now that we have all the components in place, let's update lib/main.dart. The home of the MaterialApp, meaning the initial page shown to the user, will be the LoginPage if the user is not authenticated, and the AccountPage if the user is authenticated. We also included some theming to make the app look a bit nicer.

<$CodeTabs>

dart

import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/pages/account_page.dart';
import 'package:supabase_quickstart/pages/login_page.dart';

Future<void> main() async {
  await Supabase.initialize(
    url: 'YOUR_SUPABASE_URL',
    publishableKey: 'YOUR_SUPABASE_PUBLISHABLE_KEY',
  );
  runApp(const MyApp());
}

final supabase = Supabase.instance.client;

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Supabase Flutter',
      theme: ThemeData.dark().copyWith(
        primaryColor: Colors.green,
        textButtonTheme: TextButtonThemeData(
          style: TextButton.styleFrom(
            foregroundColor: Colors.green,
          ),
        ),
        elevatedButtonTheme: ElevatedButtonThemeData(
          style: ElevatedButton.styleFrom(
            foregroundColor: Colors.white,
            backgroundColor: Colors.green,
          ),
        ),
      ),
      home: supabase.auth.currentSession == null
          ? const LoginPage()
          : const AccountPage(),
    );
  }
}

extension ContextExtension on BuildContext {
  void showSnackBar(String message, {bool isError = false}) {
    ScaffoldMessenger.of(this).showSnackBar(
      SnackBar(
        content: Text(message),
        backgroundColor: isError
            ? Theme.of(this).colorScheme.error
            : Theme.of(this).snackBarTheme.backgroundColor,
      ),
    );
  }
}

</$CodeTabs>

Once that's done, run this in a terminal window to launch on Android or iOS:

bash

flutter run

Or for web, run the following command to launch it on localhost:3000

bash

flutter run -d web-server --web-hostname localhost --web-port 3000

And then open the browser to localhost:3000 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.

Making sure we have a public bucket

We will be storing the image as a publicly sharable image. Make sure your avatars bucket is set to public, and if it is not, change the publicity by clicking the dot menu that appears when you hover over the bucket name. You should see an orange Public badge next to your bucket name if your bucket is set to public.

Adding image uploading feature to account page

We will use image_picker plugin to select an image from the device.

Add the following line in your pubspec.yaml file to install image_picker:

yaml

image_picker: ^1.0.5

Using image_picker requires some additional preparation depending on the platform. Follow the instruction on README.md of image_picker on how to set it up for the platform you are using.

Once you are done with all of the above, it is time to dive into coding.

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

<$CodeTabs>

dart

import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/main.dart';

class Avatar extends StatefulWidget {
  const Avatar({
    super.key,
    required this.imageUrl,
    required this.onUpload,
  });

  final String? imageUrl;
  final void Function(String) onUpload;

  @override
  State<Avatar> createState() => _AvatarState();
}

class _AvatarState extends State<Avatar> {
  bool _isLoading = false;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        if (widget.imageUrl == null || widget.imageUrl!.isEmpty)
          Container(
            width: 150,
            height: 150,
            color: Colors.grey,
            child: const Center(
              child: Text('No Image'),
            ),
          )
        else
          Image.network(
            widget.imageUrl!,
            width: 150,
            height: 150,
            fit: BoxFit.cover,
          ),
        ElevatedButton(
          onPressed: _isLoading ? null : _upload,
          child: const Text('Upload'),
        ),
      ],
    );
  }

  Future<void> _upload() async {
    final picker = ImagePicker();
    final imageFile = await picker.pickImage(
      source: ImageSource.gallery,
      maxWidth: 300,
      maxHeight: 300,
    );
    if (imageFile == null) {
      return;
    }
    setState(() => _isLoading = true);

    try {
      final bytes = await imageFile.readAsBytes();
      final fileExt = imageFile.path.split('.').last;
      final fileName = '${DateTime.now().toIso8601String()}.$fileExt';
      final filePath = fileName;
      await supabase.storage.from('avatars').uploadBinary(
            filePath,
            bytes,
            fileOptions: FileOptions(contentType: imageFile.mimeType),
          );
      final imageUrlResponse = await supabase.storage
          .from('avatars')
          .createSignedUrl(filePath, 60 * 60 * 24 * 365 * 10);
      widget.onUpload(imageUrlResponse);
    } on StorageException catch (error) {
      if (mounted) {
        context.showSnackBar(error.message, isError: true);
      }
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    }

    setState(() => _isLoading = false);
  }
}

</$CodeTabs>

And then we can add the widget to the Account page as well as some logic to update the avatar_url whenever the user uploads a new avatar.

<$CodeTabs>

dart

import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'package:supabase_quickstart/components/avatar.dart';
import 'package:supabase_quickstart/main.dart';
import 'package:supabase_quickstart/pages/login_page.dart';

class AccountPage extends StatefulWidget {
  const AccountPage({super.key});

  @override
  State<AccountPage> createState() => _AccountPageState();
}

class _AccountPageState extends State<AccountPage> {
  final _usernameController = TextEditingController();
  final _websiteController = TextEditingController();

  String? _avatarUrl;
  var _loading = true;

  /// Called once a user id is received within `onAuthenticated()`
  Future<void> _getProfile() async {
    setState(() {
      _loading = true;
    });

    try {
      final userId = supabase.auth.currentSession!.user.id;
      final data =
          await supabase.from('profiles').select().eq('id', userId).single();
      _usernameController.text = (data['username'] ?? '') as String;
      _websiteController.text = (data['website'] ?? '') as String;
      _avatarUrl = (data['avatar_url'] ?? '') as String;
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  /// Called when user taps `Update` button
  Future<void> _updateProfile() async {
    setState(() {
      _loading = true;
    });
    final userName = _usernameController.text.trim();
    final website = _websiteController.text.trim();
    final user = supabase.auth.currentUser;
    final updates = {
      'id': user!.id,
      'username': userName,
      'website': website,
      'updated_at': DateTime.now().toIso8601String(),
    };
    try {
      await supabase.from('profiles').upsert(updates);
      if (mounted) context.showSnackBar('Successfully updated profile!');
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  Future<void> _signOut() async {
    try {
      await supabase.auth.signOut();
    } on AuthException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    } finally {
      if (mounted) {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (_) => const LoginPage()),
        );
      }
    }
  }

  /// Called when image has been uploaded to Supabase storage from within Avatar widget
  Future<void> _onUpload(String imageUrl) async {
    try {
      final userId = supabase.auth.currentUser!.id;
      await supabase.from('profiles').upsert({
        'id': userId,
        'avatar_url': imageUrl,
      });
      if (mounted) {
        const SnackBar(
          content: Text('Updated your profile image!'),
        );
      }
    } on PostgrestException catch (error) {
      if (mounted) context.showSnackBar(error.message, isError: true);
    } catch (error) {
      if (mounted) {
        context.showSnackBar('Unexpected error occurred', isError: true);
      }
    }
    if (!mounted) {
      return;
    }

    setState(() {
      _avatarUrl = imageUrl;
    });
  }

  @override
  void initState() {
    super.initState();
    _getProfile();
  }

  @override
  void dispose() {
    _usernameController.dispose();
    _websiteController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Profile')),
      body: ListView(
        padding: const EdgeInsets.symmetric(vertical: 18, horizontal: 12),
        children: [
          Avatar(
            imageUrl: _avatarUrl,
            onUpload: _onUpload,
          ),
          const SizedBox(height: 18),
          TextFormField(
            controller: _usernameController,
            decoration: const InputDecoration(labelText: 'User Name'),
          ),
          const SizedBox(height: 18),
          TextFormField(
            controller: _websiteController,
            decoration: const InputDecoration(labelText: 'Website'),
          ),
          const SizedBox(height: 18),
          ElevatedButton(
            onPressed: _loading ? null : _updateProfile,
            child: Text(_loading ? 'Saving...' : 'Update'),
          ),
          const SizedBox(height: 18),
          TextButton(onPressed: _signOut, child: const Text('Sign Out')),
        ],
      ),
    );
  }
}

</$CodeTabs>

Congratulations, you've built a fully functional user management app using Flutter and Supabase!

Building the app

Initialize a Flutter app

Setup deep links

Main function

Set up account page

Launch!

Bonus: Profile photos

Making sure we have a public bucket

Adding image uploading feature to account page

Create an upload widget

Add the new widget

See also

Build a User Management App with Flutter

Building the app

Initialize a Flutter app

Setup deep links

Main function

Set up a login page

Set up account page

Launch!

Bonus: Profile photos

Making sure we have a public bucket

Adding image uploading feature to account page

Create an upload widget

Add the new widget

See also