DocuMind AI documentation

DocuMind AI is a premium Flutter application that lets users upload documents (PDF, TXT), scan physical pages via OCR, and then ask AI-powered questions about the content. Built with Firebase, OpenAI GPT-4o, RevenueCat subscriptions, and Google AdMob monetization.

Target users

Students, lawyers, researchers, business professionals, teachers — anyone who reads long documents and needs quick, AI-driven answers.

Tech stack

System requirements

External accounts required

• Firebase project — Auth, Firestore, Storage, Cloud Functions
• OpenAI API key — For GPT-4o document Q&A
• RevenueCat account — In-app subscription management
• Google AdMob account — Monetization via ads
• Apple Developer account — For iOS builds & Apple Sign-In
• Google Play Console — For Android distribution

Key dependencies

dependencies:
  flutter_riverpod: ^3.2.1       # State management
  hooks_riverpod: ^3.2.1         # Hooks + Riverpod
  go_router: ^17.1.0             # Declarative routing
  firebase_core: ^4.4.0          # Firebase initialization
  firebase_auth: ^6.1.4          # Authentication
  cloud_firestore: ^6.1.2        # Database
  firebase_storage: ^13.0.6      # File uploads
  cloud_functions: ^6.0.6        # Cloud Functions calls
  google_sign_in: ^7.2.0         # Google OAuth
  sign_in_with_apple: ^7.0.1     # Apple OAuth
  file_picker: ^10.3.10          # Document picking
  image_picker: ^1.2.1           # Camera capture
  google_mlkit_text_recognition: ^0.15.1  # OCR
  syncfusion_flutter_pdfviewer: ^32.2.7   # PDF viewing
  syncfusion_flutter_pdf: ^32.2.7         # PDF parsing
  purchases_flutter: ^9.12.2     # RevenueCat
  google_mobile_ads: ^7.0.0      # AdMob
  flutter_tts: ^4.2.5            # Text-to-Speech
  speech_to_text: ^7.3.0         # Speech-to-Text
  flutter_markdown: ^0.7.7+1     # Markdown rendering
  share_plus: ^12.0.1            # Sharing
  url_launcher: ^6.3.2           # Open URLs

1. 01

   Prerequisites — install Flutter

   Download and install Flutter SDK from the official site. Ensure it’s on your PATH.

   terminalCopy

   # Verify installation
   flutter doctor -v
   
   # Expected output: all checkmarks ✓ for Flutter, Android, iOS

2. 02

   Clone / extract the project

   Unzip the source code package or clone from your repository into a working directory.

   terminalCopy

   # Extract the archive
   unzip documind_ai.zip -d ~/projects/documind_ai
   cd ~/projects/documind_ai

3. 03

   Install Flutter dependencies

   terminalCopy

   flutter pub get

4. 04

   Set up Firebase

   Create a new Firebase project at console.firebase.google.com.

   terminalCopy

   # Install Firebase CLI
   npm install -g firebase-tools
   
   # Login to Firebase
   firebase login
   
   # Install FlutterFire CLI
   dart pub global activate flutterfire_cli
   
   # Configure Firebase for your project
   flutterfire configure --project=YOUR_FIREBASE_PROJECT_ID

   Note

   This will generate firebase_options.dart, google-services.json (Android), and GoogleService-Info.plist (iOS) automatically.
5. 05

   Enable Firebase services

   In the Firebase Console, enable the following:

   • Authentication → Enable Email/Password, Google, and Apple sign-in methods
   • Cloud Firestore → Create a database in production mode
   • Firebase Storage → Enable storage for document uploads
   • Cloud Functions → Upgrade to Blaze plan (pay-as-you-go) for function deployment
6. 06

   Deploy Cloud Functions

   The Cloud Functions serve as middleware to securely call the OpenAI API.

   terminalCopy

   cd functions
   
   # Install Node.js dependencies
   npm install
   
   # Create .env file with your OpenAI key
   echo "OPENAI_API_KEY=sk-your-openai-api-key-here" > .env
   
   # Deploy functions
   firebase deploy --only functions
   
   cd ..

   Warning

   Never commit your .env file or expose your OpenAI API key in client-side code. The Cloud Functions act as a secure proxy.
7. 07

   Configure RevenueCat (subscriptions)

   See the detailed RevenueCat setup section below.
8. 08

   Configure AdMob (ads)

   See the detailed AdMob setup section below.
9. 09

   Run the app

   terminalCopy

   # Run on Android emulator or device
   flutter run
   
   # Run on iOS simulator (macOS only)
   flutter run -d ios
   
   # Build release APK
   flutter build apk --release
   
   # Build iOS IPA
   flutter build ipa --release

Theme and branding

The primary brand color is #00A6A6 (teal). The app uses Material 3 with Google Fonts (Figtree). Edit the theme in:

theme: ThemeData(
  colorScheme: ColorScheme.fromSeed(
    seedColor: const Color(0xFF00A6A6),  // ← Change brand color here
    brightness: Brightness.light,
  ),
  useMaterial3: true,
  textTheme: GoogleFonts.figtreeTextTheme(),  // ← Change font here
),

Environment variables

Screen flow

RevenueCat simplifies in-app purchases for both iOS (App Store) and Android (Google Play). It handles receipt validation, subscription status, and cross-platform entitlements.

1. 01

   Create a RevenueCat account

   Go to app.revenuecat.com and sign up for a free account. Create a new Project.
2. 02

   Configure App Store Connect (iOS)

   • In App Store Connect, go to Users and Access → Integrations → In-App Purchase
   • Generate a Shared Secret (App-Specific)
   • Create your subscription products (e.g., pro_monthly, pro_yearly)
   • In RevenueCat dashboard → Project Settings → Apple App Store:
   • Paste your App Bundle ID and Shared Secret
   • Upload your App Store Connect API Key (P8 file)
3. 03

   Configure Google Play Console (Android)

   • In Google Play Console, go to Monetize → Subscriptions
   • Create subscription products matching iOS (e.g., pro_monthly, pro_yearly)
   • Create a Service Account with Financial Data permissions
   • Download the JSON key file
   • In RevenueCat dashboard → Project Settings → Google Play Store:
   • Upload the Service Account JSON key
   • Set the Package Name
4. 04

   Create products and entitlements in RevenueCat

   • Go to Products → Add your App Store & Play Store product IDs
   • Go to Entitlements → Create an entitlement named pro
   • Attach your products to the pro entitlement
   • Go to Offerings → Create a “Default” offering with your packages

   Warning

   The entitlement name pro must match exactly — this is what the code checks: entitlements.all['pro']?.isActive
5. 05

   Get your API keys

   In the RevenueCat dashboard, go to Project Settings → API Keys. Copy the:

   • Apple public API key (starts with appl_)
   • Google public API key (starts with goog_)
6. 06

   Update the code with your keys

   Open lib/features/subscription/providers/subscription_provider.dart and replace the placeholder keys:

   subscription_provider.dartCopy

   // Replace these with your actual RevenueCat publicly viewable API keys
   const _appleApiKey = 'appl_YOUR_REAL_APPLE_KEY_HERE';
   const _googleApiKey = 'goog_YOUR_REAL_GOOGLE_KEY_HERE';

7. 07

   Disable mock mode

   In the same file, set _useMock to false so the app uses real RevenueCat API calls:

   subscription_provider.dartCopy

   class SubscriptionNotifier {
     // Set this to false when you have real API keys
     final bool _useMock = false;  // ← Change from true to false
     ...
   }

   Tip

   When _useMock = true, the app simulates purchases for testing. Switch to false only when your RevenueCat products are fully configured.
8. 08

   Test purchases

   • iOS: Use a Sandbox Tester account (App Store Connect → Users → Sandbox Testers)
   • Android: Add your Google account as a License Tester (Google Play Console → Settings → License Testing)
   • Use RevenueCat’s Debug Logs to verify purchases: Purchases.setLogLevel(LogLevel.debug)

1. 01

   Create an AdMob account

   Go to admob.google.com and sign up. Create a new App for both Android and iOS.
2. 02

   Create ad units

   For each platform (Android & iOS), create:

   Ad typeFormatWhere it’s used

   Banner ad

   Standard banner

   Bottom of Home, Library, Chat screens

   Interstitial ad

   Full-screen

   After uploading a document
3. 03

   Update Android AdMob App ID

   Open android/app/src/main/AndroidManifest.xml and replace the test App ID:

   AndroidManifest.xmlCopy

   <meta-data
       android:name="com.google.android.gms.ads.APPLICATION_ID"
       android:value="ca-app-pub-XXXXXXXXXXXXXXXX~YYYYYYYYYY" />
       <!-- Replace with YOUR AdMob Application ID -->

4. 04

   Update iOS AdMob App ID

   Open ios/Runner/Info.plist and replace the test App ID:

   Info.plistCopy

   <key>GADApplicationIdentifier</key>
   <string>ca-app-pub-XXXXXXXXXXXXXXXX~YYYYYYYYYY</string>
   <!-- Replace with YOUR AdMob Application ID -->

5. 05

   Update ad unit IDs in code

   Open lib/features/ads/ad_provider.dart and replace all test IDs:

   ad_provider.dartCopy

   class AdUnitIds {
     static String get bannerAdUnitId {
       if (Platform.isAndroid) {
         return 'ca-app-pub-XXXXX/YYYYY'; // YOUR Android banner ID
       } else {
         return 'ca-app-pub-XXXXX/YYYYY'; // YOUR iOS banner ID
       }
     }
   
     static String get interstitialAdUnitId {
       if (Platform.isAndroid) {
         return 'ca-app-pub-XXXXX/YYYYY'; // YOUR Android interstitial ID
       } else {
         return 'ca-app-pub-XXXXX/YYYYY'; // YOUR iOS interstitial ID
       }
     }
   }

   Warning

   Never use test ad IDs in production builds. Google will reject your app or suspend your AdMob account.
6. 06

   Test with test ads first

   Google provides test ad IDs for development. These are the ones currently in the code. Only replace them when you are ready for production.

   Ad typeAndroid test IDiOS test ID

   Banner

   ca-app-pub-3940256099942544/6300978111

   ca-app-pub-3940256099942544/2934735716

   Interstitial

   ca-app-pub-3940256099942544/1033173712

   ca-app-pub-3940256099942544/4411468910
7. 07

   Ad behavior

   • Pro users automatically skip all ads (checked via isPro flag in user profile)
   • Banner ads appear for free users on key screens via the BannerAdWidget
   • Interstitial ads are shown after user actions (e.g., document uploads) via InterstitialAdService.recordActionAndShowAdIfReady()

Changing the app name

Changing the brand color

Edit the seed color in lib/app.dart:

// Current: Teal (#00A6A6)
seedColor: const Color(0xFF00A6A6),
// Example: Deep Purple
seedColor: const Color(0xFF7C3AED),

Changing the font

Replace the Google Font in lib/app.dart:

// Current font
textTheme: GoogleFonts.figtreeTextTheme(),
// Alternatives
textTheme: GoogleFonts.interTextTheme(),
textTheme: GoogleFonts.poppinsTextTheme(),
textTheme: GoogleFonts.robotoTextTheme(),

Changing the app icon

• Android: Replace files in android/app/src/main/res/mipmap-* directories
• iOS: Replace the asset catalog at ios/Runner/Assets.xcassets/AppIcon.appiconset/
• Alternatively, use the flutter_launcher_icons package for auto-generation

Changing ad frequency

In lib/features/ads/ad_provider.dart, modify the interstitial ad frequency:

// Show interstitial every N actions (default: 1)
static const int _actionsBetweenAds = 3;  // Show every 3 uploads

Changing the AI model

Edit the Cloud Function in functions/index.js to switch OpenAI models:

// Current: GPT-4o
model: "gpt-4o"
// Cheaper alternative
model: "gpt-4o-mini"
// Cheaper still
model: "gpt-3.5-turbo"

DocuMind AI includes a built-in admin panel that runs as a Flutter Web app. When you run the project on web (flutter run -d chrome), it automatically loads the admin dashboard instead of the mobile app. The admin panel is deployed to Firebase Hosting at https://documind-ai-8f703.web.app.

Admin panel features

• Dashboard — Overview of total users (Pro, Free, Guest), new signups (today/week/month), document stats (PDF, text, image counts + storage), questions asked today, chat sessions, flashcard decks, and Pro conversion rate.
• User management — Paginated user list with search (email/name) and filter (All/Pro/Free/Guest). Click into any user to see their documents, chat sessions, flashcard decks, and folders. Admin actions: Grant/Revoke Pro, Reset daily questions, Delete user (cascading).
• Document management — Cross-user document listing with type filter (All/PDF/Text/Image). Paginated with 10 items per page.
• Content oversight — Browse all chat sessions across users with a message viewer dialog. Browse all flashcard decks with a card viewer dialog. Useful for monitoring AI response quality.
• Subscriptions — Pro user list with conversion metrics. Manually grant or revoke Pro status.
• Analytics — User growth, document breakdown (type distribution bar), feature usage stats, and user distribution visualization.
• Settings — Configure daily question limit and max AI tokens per response (stored in Firestore config/app).

Setting up admin access

1. 01
   Go to Firebase Console → Firestore → users collection.
2. 02
   Find your user document and add a field: isAdmin: true (boolean).
3. 03
   Open the admin panel and sign in with that account’s email/password. Non-admin users are denied access.

Deploying the admin panel

# Build the web release
flutter build web --release

# Deploy to Firebase Hosting
firebase deploy --only hosting

The hosting config in firebase.json points public to build/web with a SPA rewrite rule so all routes resolve to index.html.

Admin Cloud Functions

Five admin-specific Cloud Functions are included in functions/src/index.ts:

All admin functions verify isAdmin: true on the caller before executing. Deploy them with:

cd functions && npm run deploy

Project structure (admin)

lib/
├── admin_app.dart               # Admin GoRouter, theme, transitions
├── main.dart                    # kIsWeb → AdminApp, else DocuMindApp
└── features/admin/
    ├── data/
    │   └── admin_repository.dart     # Firestore queries, pagination, cache
    ├── providers/
    │   ├── admin_auth_provider.dart   # Auth state, isAdmin check
    │   └── admin_providers.dart       # Dashboard stats, config providers
    └── presentation/
        ├── screens/
        │   ├── admin_login_screen.dart
        │   ├── dashboard_screen.dart
        │   ├── users_list_screen.dart
        │   ├── user_detail_screen.dart
        │   ├── documents_list_screen.dart
        │   ├── chat_sessions_screen.dart
        │   ├── flashcard_decks_screen.dart
        │   ├── subscriptions_screen.dart
        │   ├── analytics_screen.dart
        │   └── settings_screen.dart
        └── widgets/
            ├── admin_scaffold.dart       # Responsive sidebar + layout
            ├── pagination_controls.dart  # Reusable pagination
            └── stat_card.dart            # Reusable metric card

Firestore indexes

Some admin queries require composite indexes. When you first use a filtered view (e.g., filtering users by Pro status, or documents by type), Firestore will throw an error containing a link to create the required index. Check the browser’s debug console and click the link to create each index automatically.

“OPENAI_API_KEY environment variable is missing”

Create a .env file in the functions/ directory:

echo "OPENAI_API_KEY=sk-your-api-key" > functions/.env
firebase deploy --only functions

Firebase Auth: “Sign-In provider is not enabled”

Go to Firebase Console → Authentication → Sign-in method → Enable the provider (Email, Google, Apple).

AdMob: “Failed to load ad”

• Ensure you are using test ad IDs during development
• Real ads may take 24-48 hours to start serving after creating ad units
• Check that the App ID in AndroidManifest.xml / Info.plist matches your AdMob dashboard
• Ensure the device has internet connectivity

RevenueCat: “No offerings found”

• Verify products are created in both App Store Connect / Google Play Console
• Ensure products are attached to an Offering in RevenueCat dashboard
• Check that your API keys are correct and _useMock = false
• For iOS, subscriptions may take up to 24 hours to propagate in sandbox

Build fails: “SDK version constraint”

Ensure your Flutter SDK version is 3.41.2 or higher:

flutter upgrade
flutter --version

iOS build fails: CocoaPods issues

cd ios
pod deintegrate
pod install --repo-update
cd ..
flutter clean
flutter pub get
flutter run

Syncfusion license warning

Syncfusion provides a community license free for individuals and small businesses (<$1M revenue). Register at syncfusion.com/products/communitylicense and add the license key in main.dart:

SyncfusionLicense.registerLicense("YOUR-LICENSE-KEY");

Camera / microphone permission denied

iOS: Descriptions are already configured in Info.plist for NSMicrophoneUsageDescription and NSSpeechRecognitionUsageDescription.

Android: Runtime permissions are requested automatically via the plugins. Ensure CAMERA, RECORD_AUDIO permissions are in AndroidManifest.xml if missing.

Every version published so far. Updates are free for the life of the item.

We provide 6 months of support from the date of purchase.

Our support covers:

• Bug fixes and issues related to the source code
• Installation & configuration assistance
• Firebase, RevenueCat, and AdMob setup guidance
• General questions about features and customization

Support does not include:

• Custom feature development or modification
• Third-party plugin integration beyond what’s included
• App Store / Play Store submission support

What support covers

• Six months of support from purchase, extendable at checkout
• Support covers bugs in the template and questions about how it is put together
• It does not cover custom feature work, third-party API changes or store review outcomes
• The Regular licence covers one free end product. Charging users for the app itself needs the Extended licence