Zeyo Backend

A Node.js/TypeScript backend for managing loans, crypto transactions, and fiat payments, using Express, MongoDB, Stripe, and Ethers.js.

Features

• User Authentication (JWT-based)
• Loan Management (create, fetch, repay loans)
• Crypto Services (borrow and repay tokens via Ethers.js)
• Fiat Services (Stripe integration for account creation, transfers, and payouts)
• PDF Generation (via Puppeteer)
• MongoDB for persistent storage

Prerequisites

• Node.js (v16+ recommended)
• npm or yarn
• MongoDB instance (local or remote)
• Stripe account (for API keys)
• Infura account (for Ethereum RPC)

Environment Variables

Create a .env file in the root directory with the following:

PORT=3000
MONGODB_URI=mongodb://127.0.0.1:27017/zeyo
JWT_SECRET=your_jwt_secret
INFURA_PROJECT_ID=your_infura_project_id
PRIVATE_KEY=your_ethereum_private_key
STRIPE_SECRET_KEY=your_stripe_secret_key

Installation

git clone https://github.com/yourusername/zeyo-backend.git
cd zeyo-backend
npm install
# or
yarn install

Running the Project

npm run dev
# or
yarn dev

The server will start on the port specified in your .env file (default: 3000).

Project Structure

src/
  config/         # Configuration files (db, utils, constants)
  controllers/    # Express route controllers
  middleware/     # Express middleware (e.g., auth)
  models/         # Mongoose models
  services/       # Business logic (auth, fiat, crypto, loan)
  utils/          # Utility files (e.g., ABIs)

API Endpoints

Authentication

• POST /api/auth/register - Register a new user
• POST /api/auth/login - Login user

Loans

• POST /api/loans - Create a new loan
• GET /api/loans/user - Get all loans for a user
• GET /api/loans/:id - Get loan by ID
• POST /api/loans/pdf - Generate loan PDF

Crypto

• POST /api/crypto/borrow - Borrow tokens
• POST /api/crypto/repay - Repay borrowed tokens

Fiat

• POST /api/fiat/create-user - Create Stripe user
• POST /api/fiat/transfer - Transfer money
• POST /api/fiat/payment-intent - Create payment intent

Development

• Uses TypeScript for type safety
• Linting and formatting via ESLint and Prettier
• Error handling implemented in all services and controllers

Dependencies

• express: Web framework
• mongoose: MongoDB ODM
• jsonwebtoken: JWT authentication
• bcrypt: Password hashing
• ethers: Ethereum interactions
• stripe: Payment processing
• puppeteer: PDF generation
• dotenv: Environment variables
• joi: Request validation

Error Handling

The application implements comprehensive error handling:

• Input validation using Joi
• Try-catch blocks in all async operations
• Custom error messages for different scenarios
• Proper HTTP status codes for different error types

Security Features

• Password hashing using bcrypt
• JWT-based authentication
• Environment variables for sensitive data
• Input validation and sanitization
• Secure HTTP headers

License

MIT