Veridion Backend

A scalable NestJS backend application built with TypeScript and following Domain-Driven Design (DDD) principles with a layered architecture.

🏗️ Architecture

This project follows a layered architecture pattern with clear separation of concerns:

src/
├── config/           # Configuration & environment validation
├── core/             # Logger, errors, utilities
├── domain/           # Entities, value objects, ports/interfaces
├── application/      # Services, use cases
├── infrastructure/   # External services
├── interfaces/       # Controllers, DTOs, presenters
├── modules/          # Feature modules that bind everything
└── test-utils/       # Testing utilities

🎯 Design Principles

• Domain-Driven Design: Business logic lives in the domain layer
• Clean Architecture: Dependencies point inward, framework-agnostic domain
• Separation of Concerns: Each layer has a specific responsibility
• Testability: Easy to mock and test each layer independently

🚀 Quick Start

Prerequisites

• Node.js (v18 or higher)
• npm (v8 or higher)

Installation

1. Clone the repository

   git clone https://github.com/Veridion-Id/Backend-Veridion.git
   cd Backend-Veridion

2. Install dependencies

   npm install

3. Environment setup

   # Copy environment template
   cp .env.example .env
   
   # Edit .env with your configuration
   nano .env

4. Start the application

   # Development mode
   npm run start:dev
   
   # Production mode
   npm run build
   npm run start:prod

📚 Available Scripts

Script	Description
npm run start	Start the application
npm run start:dev	Start in development mode with hot reload
npm run start:debug	Start in debug mode
npm run start:prod	Start in production mode
npm run build	Build the application
npm run test	Run unit tests
npm run test:watch	Run tests in watch mode
npm run test:cov	Run tests with coverage
npm run test:e2e	Run end-to-end tests
npm run lint	Run ESLint
npm run format	Format code with Prettier

🛠️ Technology Stack

• Framework: NestJS - Progressive Node.js framework
• Language: TypeScript - Strict mode enabled
• Backend Services: Firebase Admin SDK - Authentication and Firestore
• Documentation: Swagger/OpenAPI - Available at /docs
• Testing: Jest - Unit and E2E testing
• Code Quality: ESLint + Prettier

📁 Project Structure

Core Layers

src/config/

Application configuration and environment validation.

src/domain/

• Entities: Core business objects
• Value Objects: Immutable objects with no identity
• Ports: Interfaces for external dependencies

src/application/

Business logic and use cases. This layer orchestrates domain objects.

src/infrastructure/

External services implementation (databases, APIs, file systems).

src/interfaces/

• Controllers: HTTP request handlers
• DTOs: Data Transfer Objects for validation
• Presenters: Response formatting

src/modules/

Feature modules that wire together domain, application, infrastructure, and interface layers.

🔧 Configuration

Environment Variables

Create a .env file in the root directory:

# Application Configuration
PORT=3000
NODE_ENV=development

# Firebase Configuration
FIREBASE_PROJECT_ID=your-firebase-project-id
FIREBASE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\nYOUR_PRIVATE_KEY_HERE\n-----END PRIVATE KEY-----\n"
FIREBASE_CLIENT_EMAIL=your-service-account@your-project.iam.gserviceaccount.com

# Add your other configuration variables here

📖 API Documentation

Once the application is running, visit:

• Swagger UI: http://localhost:3000/docs
• Health Check: http://localhost:3000/

🧪 Testing

Unit Tests

npm run test

E2E Tests

npm run test:e2e

Test Coverage

npm run test:cov

🎨 Code Style

The project follows consistent code style:

• Prettier: Single quotes, no semicolons, trailing commas
• ESLint: TypeScript-specific rules
• Conventional Commits: For commit messages

Format Code

npm run format

Lint Code

npm run lint

🚀 Deployment

Build for Production

npm run build

🤝 Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature/amazing-feature
3. Commit your changes: git commit -m 'feat: add amazing feature'
4. Push to the branch: git push origin feature/amazing-feature
5. Open a Pull Request

Commit Convention

We use Conventional Commits:

• feat: New features
• fix: Bug fixes
• docs: Documentation changes
• style: Code style changes
• refactor: Code refactoring
• test: Test additions or changes
• chore: Build process or auxiliary tool changes

📄 License

This project is licensed under the ISC License - see the LICENSE file for details.

🆘 Support

If you have any questions or need help:

1. Check the Issues page
2. Create a new issue with detailed information
3. Contact the development team

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Happy Coding! 🚀