N3xus

N3xus - An integrated chat platform with multiple AI models, where users can switch between models, create new chats, organize conversations, and compare responses.

Overview

Nexus is a complete SaaS application built with Next.js 15 that allows users to interact with the most advanced AI models through a modern and intuitive interface. The platform offers robust authentication, subscription system, usage control, and an optimized real-time chat experience.

Key Features

• Multiple AI Models: Access to GPT-5, Gemini 2.5, Claude 4 Sonnet, and DeepSeek V3
• Integrated Web Search: Ability to search for up-to-date information on the web during conversations
• Complete Authentication: Login system with Google and email/password using Better Auth
• Subscription System: Stripe integration for Pro plans with custom limits
• Usage Control: Detailed monitoring of daily, weekly, and monthly usage
• Real-Time Chat: Streaming interface with markdown and syntax highlighting support
• Responsive Design: Interface optimized for desktop and mobile
• Dark/Light Theme: Full theme support with next-themes
• Sharing: Public conversation sharing system
• History: Complete navigation through conversation history

Technical Architecture

Main Stack

• Frontend: Next.js 15 with App Router, React 19, TypeScript
• Styling: Tailwind CSS 4 with Radix UI components
• Authentication: Better Auth with Stripe integration
• Database: PostgreSQL with Prisma ORM
• Payments: Stripe for subscriptions and billing
• AI: AISDK + OpenRouter for unified model access
• Deploy: Optimized for Vercel

Project Structure

nexus/
├── app/                          # App Router (Next.js 15)
│   ├── api/                      # API Routes
│   │   ├── auth/                 # Authentication endpoints
│   │   └── chat/                 # Chat and streaming API
│   ├── chat/                     # Chat pages
│   │   ├── [id]/                 # Specific chat by ID
│   │   └── page.tsx              # Chat list
│   ├── share/[id]/               # Public sharing
│   └── generated/                # Generated Prisma client
├── components/                   # React components
│   ├── ai-elements/              # AI-specific components
│   ├── chat/                     # Chat components
│   ├── common/                   # Shared components
│   └── sidebar/                  # Side navigation
├── lib/                          # Utilities and configurations
│   ├── auth.ts                   # Better Auth configuration
│   ├── prisma.ts                 # Prisma client
│   └── openrouter.ts             # OpenRouter configuration
├── prisma/                       # Schema and migrations
├── server/                       # Server actions
└── public/                       # Static assets

Setup and Installation

Prerequisites

• Node.js 18+
• Configured accounts: OpenRouter, AISDK, Stripe, Google OAuth

Environment Variables

Create a .env.local file with the following variables:

# Database
DATABASE_URL="postgresql://..."

# Authentication
BETTER_AUTH_SECRET="your-secret-key"
GOOGLE_CLIENT_ID="your-google-client-id"
GOOGLE_CLIENT_SECRET="your-google-client-secret"

# AI Models
OPENROUTER_API_KEY="your-openrouter-key"

# Payments
STRIPE_SECRET_KEY="sk_..."
STRIPE_PUBLISHABLE_KEY="pk_..."
STRIPE_WEBHOOK_SECRET="whsec_..."

# Email (optional)
RESEND_API_KEY="re_..."

Installation

# Clone the repository
git clone <repository-url>
cd nexus

# Install dependencies
npm install

# Set up the database
npx prisma generate
npx prisma migrate deploy

# Start the development server
npm run dev

Access http://localhost:3000 to view the application.

Available Scripts

npm run dev          # Development server with Turbopack
npm run build        # Production build
npm run start        # Production server
npm run lint         # Linting with ESLint

Data Model

Main Entities

• User: Users with authentication and profiles
• Chat: Conversations with titles and metadata
• Message: Individual messages with JSON content
• Subscription: Stripe subscriptions with Pro plans
• UserUsage: Usage limit control by period

Usage Limits (Pro Plan)

• Daily: 50 prompts
• Weekly: 250 prompts
• Monthly: 1000 prompts

Deployment

Vercel (Recommended)

1. Connect the repository to Vercel
2. Configure environment variables
3. Deployment will be automatic with each push

Other Platforms

The application is compatible with any platform that supports Next.js:

• Railway
• Render
• AWS Amplify
• Netlify (with adaptations)

Security

• Authentication: Better Auth with secure sessions
• Authorization: User verification on all protected routes
• Rate Limiting: Subscription-based usage control
• Validation: Zod for data validation
• CSRF Protection: Native Next.js protection

Performance

• Server Components: Optimized server-side rendering
• Streaming: Real-time AI responses
• Caching: Intelligent route and data caching
• Code Splitting: On-demand loading
• Image Optimization: Automatic image optimization

License

This project is licensed under the MIT License. See the LICENSE file for more details.

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