NexaFX Backend

NexaFX is a Web3-powered currency exchange platform that supports real-time fiat and crypto conversions. The backend is built using NestJS and interfaces with smart contracts written in Rust on the Stellar network.

🚀 Features

• JWT-based authentication and authorization
• Role-based access control (Admin, User, Tutor)
• Multi-currency exchange system
• Blockchain integration with Stellar smart contracts
• Real-time and historical transactions tracking
• Modular, scalable NestJS architecture
• Exportable transaction data (CSV, Excel, PDF)

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🏗️ Project Architecture

nexafx-backend/
├── src/
│   ├── auth/              # JWT auth module
│   ├── users/             # User management (CRUD, roles)
│   ├── currencies/        # Fiat and crypto currency support
│   ├── transactions/      # Transaction logs and conversions
│   ├── common/            # Guards, interceptors, decorators
│   ├── config/            # Environment configs and database setup
│   └── main.ts            # Application entry point
├── migrations/            # SQL migration files (e.g. using TypeORM CLI)
├── test/                  # Unit and integration tests
├── .env.example           # Sample environment configuration
├── package.json
└── README.md

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📦 Tech Stack

• Backend: NestJS, TypeScript
• ORM: TypeORM (PostgreSQL)
• Security: JWT, Bcrypt
• Blockchain: Stellar (Rust smart contracts)
• Exporting: pdfkit, exceljs, fast-csv
• Testing: Jest, Supertest

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⚙️ Environment Variables

Create a .env file in the root directory. Refer to .env.example:

DATABASE_URL=postgresql://USER:PASSWORD@localhost:5432/nexafx
JWT_SECRET=your_secret_key
JWT_EXPIRES_IN=1d
STELLAR_NETWORK=TESTNET
STELLAR_HORIZON_URL=https://horizon-testnet.stellar.org
STELLAR_ADMIN_SECRET=your_stellar_admin_secret

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🚀 Getting Started

1. Clone the Repository

git clone https://github.com/your-org/nexafx-backend.git
cd nexafx-backend

2. Install Dependencies

npm install

3. Setup Database

npx prisma migrate dev --name init
npx prisma generate

4. Run the Application

npm run start:dev

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🧪 Running Tests

# Unit & Integration
npm run test

# E2E
npm run test:e2e

# Coverage
npm run test:cov

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🔐 Role-Based Access

• USER: Can perform standard exchange operations
• TUTOR: Manages educational content (future module)
• ADMIN: Full control of all resources

Guards are applied at controller and route levels using custom decorators and NestJS Guards.

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📁 Modules Overview

Module	Description
auth	JWT login, registration, guards
users	User CRUD, roles, profile
currencies	Supported fiat & crypto currencies
transactions	Track exchanges & conversions (CRUD)
common	Utilities, global guards, DTOs

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📄 API Documentation

Coming Soon: Swagger/OpenAPI integration for full REST endpoint visibility.

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🧱 Smart Contract Integration

• Rust-based contracts deployed on Stellar testnet
• Integration handled via service in NestJS using Horizon APIs
• Each transaction is optionally linked with a smart contract execution (future roadmap)

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📝 Commit Message Format

# Format:
type(scope): subject

# Examples:
feat(auth): implement refresh token strategy
fix(users): validate email uniqueness
chore(deps): upgrade Prisma to 5.0.0

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📌 Roadmap

• Auth Module with JWT
• Users Module with roles
• Currencies Module (Fiat + Crypto)
• Transactions Module with Stellar link
• DAO & Reward System (via Smart Contracts)
• Real-time rate updates
• Export features

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🔗 Related Repositories

• nexafx-frontend — Next.js UI
• nexafx-contracts — Rust smart contracts on Stellar

📜 License

MIT License. See LICENSE file.

📧 Contact

For inquiries, discussions, or help, feel free to reach out to us:

• 📬 Email: contact@nexacore.org
• 🗣️ Telegram: https://t.me/NexaFx
• 🐛 Issues: Open an issue for feature requests or bug reports

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