AuthNinja SDK #

A flexible Flutter authentication SDK for Firebase projects. You use it with the built-in UI or your own UI. The SDK supports email and password, Google, Apple, and Facebook sign-in. It offers strong typing, token refresh, clear errors, and reactive state.

Preview Image #

Features #

• Plug and Play UI, customizable screens • Headless mode • Email and password, Google, Apple, Facebook • Stream based state • Clear error flow • Token refresh • Simple testing with a custom repository

Installation #

dependencies: auth_ninja_sdk: path: ../

or from git hub

auth_ninja_sdk: git: url: https://github.com/McMaurice/auth-ninja-sdk ref: main

auth_ninja_sdk: ^1.0.0 firebase_core: ^3.0.0 firebase_auth: ^5.0.0 From directory:

firebase_core: ^3.0.0 firebase_auth: ^5.0.0

Firebase Setup #

Follow these steps before you use the SDK.

Firebase Project #

• Create a Firebase project • Add Android, iOS, Web • Download google-services.json for Android • Download GoogleService-Info.plist for iOS • Enable Email and Password, Google, Apple, Facebook

Android Setup #

• Add SHA1 and SHA256 in Firebase settings • Add Google reversed client id in android manifest • Add Facebook app id if you use Facebook • Add google-services plugin in Gradle files

iOS Setup #

• Add GoogleService-Info.plist • Add URL schemes for Google • Add Sign in with Apple capability • Add Facebook settings if you use Facebook

Web Setup #

• Add Firebase config to web/index.html • Add redirect domain in Firebase console • Enable each provider

Usage #

You choose UI mode or headless mode.

Initialize Firebase #

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(
    options: DefaultFirebaseOptions.currentPlatform,
  );
  runApp(MyApp());
}

Mode A: Built-in UI #

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: AuthNinjaScreen(
        initialMode: AuthMode.login,
        config: AuthConfig(
          loginTitle: 'Welcome Back!',
          signUpTitle: 'Create Account',
          enableGoogleAuth: true,
          enableAppleAuth: true,
          enableFacebookAuth: true,
          primaryColor: Colors.blue,
        ),
        onApplePressed: () => const HomeScreen(),
        onGooglePressed: () => const HomeScreen(),
      ),
    );
  }
}

Mode B: Headless #

import 'package:auth_ninja_sdk/auth_ninja_sdk.dart';

final ninja = AuthNinja.instance;

void signInUser() async {
  final state = await ninja.signInWithEmail(
    'user@example.com',
    'password123',
  );

  if (state is Authenticated) {
    print(state.user.email);
  } else {
    print('Authentication failed');
  }
}

Connecting Custom UI #

Future<void> submitLogin(String email, String password) async {
  final result = await AuthNinja.instance.signInWithEmail(email, password);

  if (result is Authenticated) {
    // Navigate to HomeScreen
    // Example:
    // Navigator.pushReplacement(context, MaterialPageRoute(builder: (_) => HomeScreen()));
  } else if (result is AuthError) {
    // Show error message to user
    // Example:
    // ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(result.message)));
  }
}

Provider Setup #

Each provider needs simple steps.

Email and Password #

• Enable in Firebase console

Google #

Android • Add SHA keys • Add reversed client id in manifest

iOS • Add reversed client id in Info.plist

Web • Add redirect domain

Apple #

iOS • Add Apple capability • Add bundle id in Apple developer panel

Web • Add domain to Apple services

Facebook #

Android • Add Facebook app id • Add key hash in Facebook developer panel

iOS • Add FacebookAppID in Info.plist

Web • Add OAuth redirect domain

API Summary #

AuthNinja.instance
  .signInWithEmail
  .signUpWithEmail
  .resetPassword
  .signInWithGoogle
  .signInWithApple
  .signInWithFacebook
  .signOut
  .authStateChanges
  .currentUser helpers
  .token check and refresh
  .ensureValidToken

// Example
final info = AuthNinja.instance.getCurrentUserInfo();
print(info);

License #

MIT License, short form.

Copyright (c) 2025 AuthNinja

Permission is granted to use, copy, modify, and distribute this software. This software is provided without warranty.