Backend API Overview

The Backend API is a production-ready NestJS application that provides secure AI proxy services, user authentication, and usage analytics for the GoGrab platform.

Key Features

🔐 Authentication & Authorization

• JWT-based authentication
• Password hashing with bcrypt
• Role-based access control
• Secure session management

🤖 AI Proxy Services

• OpenAI Integration - GPT-4o, GPT-4o-mini, GPT-3.5-turbo
• Anthropic Integration - Claude 3.5 Sonnet, Claude 3 Opus
• Google Integration - Gemini Pro
• Automatic cost calculation
• Usage tracking per user

📊 Analytics & Tracking

• Real-time usage statistics
• Cost tracking per request
• Provider and model breakdown
• Historical data analysis

🔒 Security Features

• CORS configuration
• Rate limiting (100 req/min)
• Request validation
• Environment-based configuration

Architecture

Backend API
├── Auth Module          # User authentication & JWT
├── AI Module            # AI proxy for all providers
├── Analytics Module     # Usage tracking & stats
└── MongoDB Integration  # Data persistence

Quick Start

1. Install Dependencies

yarn install --ignore-engines

2. Configure Environment

Create .env.local in project root:

MONGODB_CONNECTION_STRING=mongodb+srv://...
MONGODB_DATABASE=gograb-api
OPENAI_API_KEY=sk-...
ANTHROPIC_API_KEY=sk-ant-...
GOOGLE_API_KEY=...
JWT_SECRET=your-secret-key

3. Start the Server

npx nx serve backend-api

Server will run on: http://localhost:3000/api

API Endpoints

Authentication

• POST /api/auth/register - Register new user
• POST /api/auth/login - Login user
• GET /api/auth/profile - Get user profile

AI Services (Requires Auth)

• POST /api/ai/openai/chat - OpenAI completion
• POST /api/ai/anthropic/messages - Anthropic completion
• POST /api/ai/google/generate - Google Gemini completion

Analytics (Requires Auth)

• GET /api/ai/usage - Get usage statistics
• GET /api/ai/usage/providers - Get provider breakdown

Technologies Used

• NestJS - Progressive Node.js framework
• MongoDB - Document database with Mongoose
• JWT - JSON Web Tokens for authentication
• TypeScript - Type-safe development
• class-validator - Request validation
• bcrypt - Password hashing

Next Steps

• API Reference - Complete API documentation
• Setup Guide - Detailed setup instructions
• Security Guide - Security best practices
• Frontend Integration - Connect your frontend

Project Structure

apis/backend-api/
├── src/
│   ├── app/
│   │   ├── auth/          # Authentication module
│   │   ├── ai/            # AI proxy module
│   │   └── app.module.ts  # Root module
│   └── main.ts            # Application entry
libs/
├── api-contracts/         # Shared types (FE/BE)
└── backend-core/          # MongoDB schemas

Support

For issues or questions:

1. Check the Troubleshooting Guide
2. Review the API Reference
3. See the Setup Guide