1. Key Features of the Multi-Wallet Flutter App

a. User Features

• User Registration/Login: Allow users to sign up and log in via email, phone number, or social media (Google/Facebook).
• Wallet Creation: Enable users to create multiple wallets for different purposes (e.g., cryptocurrency, gift cards, loyalty points).
• Wallet Management: Manage and switch between different wallets, with each wallet having its own balance and transaction history.
• Deposit & Withdraw: Allow users to deposit funds (e.g., transferring crypto to a wallet, adding money to a bank wallet, or receiving loyalty points) and withdraw funds to an external account.
• Transaction History: Provide users with the ability to view past transactions (withdrawals, deposits, transfers).
• Currency Support: Allow multiple currencies to be stored in each wallet, including digital and fiat currencies.
• QR Code Scanning: Users can scan QR codes for wallet addresses or for transferring funds.
• Balance Overview: Provide an overall view of the user’s combined wallet balances (across different wallet types).
• Security Features: Implement 2-factor authentication (2FA) and PIN/Password Protection for transactions.
• Push Notifications: Notify users of important events, such as successful deposits, withdrawals, or promotional offers.
• In-app Payment Integration: Integration with payment gateways such as Stripe, PayPal, or Apple Pay for fiat wallet support.

b. Admin Panel Features

• User Management: Admin can manage users, view wallets, transaction history, and report fraud.
• Wallet Management: Admin can monitor wallet activity, approve or reject wallet withdrawals, and add/remove wallet types.
• Transaction Management: Admin can view all transactions in the system, approve/disapprove them, and apply fraud detection algorithms.
• Reporting & Analytics: Analytics on wallet usage, most active users, transactions, etc.
• Push Notifications: Admin can send promotional or important messages to all users.

2. Technology Stack

a. Front-End (Mobile App - Flutter)

• Flutter 3.x (cross-platform for both iOS and Android)
  • Flutter provides the capability to create beautiful and performant apps for both platforms using a single codebase.
• Dart (the programming language used by Flutter).

b. Back-End

• Node.js + Express.js (for REST APIs to handle wallet management, transactions, and user data)
  • Node.js is a great choice for building scalable and real-time applications, especially in a financial setting.
• Database:
  • MongoDB (NoSQL database) for storing user and wallet information securely.
  • MySQL/PostgreSQL if a relational database is preferred (for structured data).
• Blockchain Integration (for Cryptocurrency Wallets):
  • Ethereum Web3.js or BitcoinJS for handling blockchain interactions like deposits and withdrawals for cryptocurrency wallets.
• Payment Gateway Integration:
  • Stripe API or PayPal API for handling fiat transactions.
  • Plaid API or similar for bank account linking.
• Authentication:
  • Firebase Authentication or OAuth for secure user login and registration.
• Push Notifications:
  • Firebase Cloud Messaging (FCM) for sending push notifications.
• Security:
  • AES Encryption for securing wallet data and transactions.
  • JWT (JSON Web Tokens) for user authentication and secure token generation.
  • 2FA using Authy or Google Authenticator for additional transaction security.

c. Admin Panel

• React.js (for building the front-end of the admin panel).
• Node.js for handling the back-end APIs and connecting to the database.
• MongoDB/MySQL for storing user, wallet, and transaction data.

3. App Flow and UI/UX Design

a. User Flow

1. Splash Screen: Display the logo and brand message.
2. Login/Sign-up Screen:
   • Allow users to log in or create an account (via email, phone, or social login).
   • Support 2FA or PIN code for security.
3. Dashboard/Home Screen:
   • Display an overview of the user's wallet(s) with balances.
   • Offer a button to create a new wallet or view existing wallets.
   • Show wallet types: Cryptocurrency Wallets, Fiat Wallets, Gift Cards, Loyalty Points, etc.
4. Wallet Detail Screen:
   • Allow users to see detailed information about the wallet (balance, transaction history, etc.).
   • Options to deposit, withdraw, and transfer funds.
   • Show QR Code for receiving payments.
5. Transactions Screen:
   • View detailed transaction history with options to filter by date or wallet.
6. Settings Screen:
   • Change personal information, wallet preferences, and security settings (PIN/Password, 2FA).
7. Notifications: Show real-time notifications (e.g., successful transactions, wallet updates).
8. Logout: Secure logout option with the ability to clear sensitive data.

b. Admin Panel Flow

1. Login: Admin login with secure access (Username/Password).
2. Dashboard: A summary of:
   • Total number of users.
   • Number of wallets created.
   • Transaction statistics (successful, pending, failed).
3. User Management: Admin can view users, manage wallets, and monitor transactions.
4. Wallet Management: Approve or reject wallet withdrawals, manage wallet types (add/remove).
5. Transaction Management: Approve or decline specific transactions.
6. Analytics: View app usage statistics, transaction volume, and user activity.
7. Send Notifications: Send promotional messages or alerts to all users.

4. Code Examples

a. Flutter Code for Creating Wallets