Architecture Overview

AI SaaS Template is built with a modern, scalable architecture that follows industry best practices. This document provides an in-depth look at the system design, components, and architectural patterns used throughout the application.

System Architecture

High-Level Architecture

Core Components

1. Frontend Layer (Next.js App Router)

• Pages & Routing: App Router with internationalized routes
• Components: Reusable UI components with Radix UI
• State Management: Zustand for client-side state
• Styling: Tailwind CSS with custom design system
• Data Fetching: SWR for caching and synchronization

2. Backend Layer (Next.js API Routes)

• API Endpoints: RESTful APIs with type-safe routing
• Authentication: AI SaaSr Auth with multiple providers
• Database: Drizzle ORM with PostgreSQL
• File Handling: Secure upload and storage management
• Payment Processing: Stripe integration with webhooks

3. Data Layer

• Database: PostgreSQL with optimized schema
• ORM: Drizzle for type-safe database operations
• Caching: Redis for session and data caching
• File Storage: Cloudflare R2 for static assets

Authentication Flow

Multi-Provider Authentication

Authentication Features

• Session Management: Database-persisted sessions with configurable expiration
• Role-Based Access Control: Admin, user, and custom role permissions
• Social Login: GitHub, Google OAuth integration
• Security: Password hashing, CSRF protection, secure cookies
• Password Reset: Email-based password recovery flow

Database Design

Core Tables

Users Table

CREATE TABLE users (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  email VARCHAR(255) UNIQUE NOT NULL,
  name VARCHAR(255),
  image TEXT,
  role VARCHAR(50) DEFAULT 'user',
  created_at TIMESTAMP DEFAULT NOW(),
  updated_at TIMESTAMP DEFAULT NOW()
);

Sessions Table

CREATE TABLE sessions (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id UUID REFERENCES users(id) ON DELETE CASCADE,
  token VARCHAR(255) UNIQUE NOT NULL,
  expires_at TIMESTAMP NOT NULL,
  created_at TIMESTAMP DEFAULT NOW()
);

Files Table

CREATE TABLE files (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id UUID REFERENCES users(id) ON DELETE CASCADE,
  filename VARCHAR(255) NOT NULL,
  original_name VARCHAR(255) NOT NULL,
  mime_type VARCHAR(100) NOT NULL,
  size INTEGER NOT NULL,
  url TEXT NOT NULL,
  created_at TIMESTAMP DEFAULT NOW()
);

Payments Table

CREATE TABLE payments (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id UUID REFERENCES users(id) ON DELETE CASCADE,
  stripe_customer_id VARCHAR(255),
  stripe_subscription_id VARCHAR(255),
  status VARCHAR(50) NOT NULL,
  plan VARCHAR(50) NOT NULL,
  amount INTEGER NOT NULL,
  currency VARCHAR(3) DEFAULT 'usd',
  created_at TIMESTAMP DEFAULT NOW(),
  updated_at TIMESTAMP DEFAULT NOW()
);

Database Relationships

File Management Architecture

Upload Flow

File Management Features

• Secure Uploads: Validation, size limits, and type restrictions
• Image Processing: Thumbnail generation and optimization
• Access Control: User-based file permissions
• Cloud Storage: Integration with Cloudflare R2/AWS S3
• Metadata Tracking: File information and usage analytics

Payment System Architecture

Stripe Integration

Payment Features

• Subscription Management: Multiple plans with billing cycles
• Webhook Processing: Real-time payment event handling
• Invoice Generation: Automated billing and receipts
• Trial Periods: Configurable free trial functionality
• Payment Recovery: Failed payment retry logic

Testing Architecture

Test Structure

• Unit Tests: Component logic and utility functions
• Integration Tests: API endpoints and database operations
• E2E Tests: Complete user workflows and scenarios
• Visual Tests: Screenshot comparison for UI consistency
• Performance Tests: Load testing and optimization

Internationalization Architecture

i18n Structure

i18n Features

• Route-Based Localization: Automatic locale detection
• Message Management: Centralized translation files
• Dynamic Content: Runtime language switching
• SEO Optimization: Localized meta tags and URLs
• Fallback Handling: Default language fallbacks

Security Architecture

Security Layers

1. Application Security

   • CSRF protection with tokens
   • XSS prevention with sanitization
   • SQL injection protection with ORM
   • Rate limiting on API endpoints

2. Authentication Security

   • Secure password hashing (bcrypt)
   • JWT token validation
   • Session management with secure cookies
   • OAuth provider integration

3. Data Security

   • Database encryption at rest
   • Secure file upload validation
   • Environment variable protection
   • API key management

4. Infrastructure Security

   • HTTPS enforcement
   • Security headers (CSP, HSTS)
   • Dependency vulnerability scanning
   • Regular security updates

Performance Optimization

Frontend Optimization

• Code Splitting: Dynamic imports and route-based splitting
• Image Optimization: Next.js Image component with WebP
• Caching: Browser caching and CDN optimization
• Bundle Analysis: Tree shaking and dead code elimination

Backend Optimization

• Database Indexing: Optimized queries and indexes
• API Caching: Response caching with Redis
• Connection Pooling: Database connection optimization
• Lazy Loading: On-demand resource loading

Deployment Architecture

Production Deployment

Deployment Features

• Automated Deployment: GitHub Actions CI/CD pipeline
• Environment Management: Staging and production environments
• Health Monitoring: Application performance monitoring
• Rollback Capability: Quick rollback on deployment issues
• Scalability: Auto-scaling based on traffic

Monitoring & Analytics

Application Monitoring

• Error Tracking: Real-time error monitoring and alerting
• Performance Metrics: Response times and resource usage
• User Analytics: User behavior and engagement tracking
• Business Metrics: Revenue, conversions, and growth metrics

This architecture provides a solid foundation for building scalable, secure, and maintainable SaaS applications. The modular design allows for easy extension and customization based on specific business requirements.