Sema Translation API - Architecture Overview

🏗️ Project Structure

This FastAPI application follows industry best practices for maintainable, scalable APIs:

Directory Structure

app/
├── main.py                     # Application entry point & FastAPI instance
├── api/v1/endpoints.py         # API route handlers (versioned)
├── core/                       # Core configuration & setup
│   ├── config.py              # Settings management
│   ├── logging.py             # Structured logging setup
│   └── metrics.py             # Prometheus metrics definitions
├── middleware/                 # Custom middleware
│   └── request_middleware.py  # Request tracking & metrics
├── models/schemas.py           # Pydantic data models
├── services/translation.py    # Business logic & model management
└── utils/helpers.py           # Utility functions

🔧 Design Principles

1. Separation of Concerns

API Layer: Route definitions and request/response handling
Service Layer: Business logic and model operations
Core Layer: Configuration, logging, and metrics
Models Layer: Data validation and serialization

2. Dependency Injection

Settings injected via Pydantic Settings
Services accessed through proper imports
Middleware applied declaratively

3. Configuration Management

Environment-based configuration
Type-safe settings with Pydantic
Centralized configuration in core/config.py

4. Observability

Structured JSON logging with structlog
Prometheus metrics for monitoring
Request tracking with unique IDs
Health check endpoints

🚀 Key Features

Enterprise-Grade Features

Rate Limiting: IP-based rate limiting with SlowAPI
Request Tracking: Unique request IDs for debugging
Metrics Collection: Prometheus metrics for monitoring
Structured Logging: JSON logs for easy parsing
Health Checks: Comprehensive health monitoring

API Design

Versioned Routes: /api/v1/ for future compatibility
OpenAPI Documentation: Auto-generated Swagger UI
Type Safety: Full Pydantic validation
Error Handling: Graceful error responses

Performance

Async/Await: Full asynchronous request handling
Model Caching: Models loaded once at startup
Efficient Translation: CTranslate2 optimization

🔒 Security (Testing Phase)

Current State

Authentication removed for testing phase
Rate limiting active (60 req/min per IP)
Input validation with Pydantic
CORS configured for development

Future Integration Points

Supabase authentication ready
User tracking infrastructure in place
Usage analytics for billing prepared

📊 Monitoring & Observability

Metrics Available

Request count by endpoint and status
Request duration histograms
Translation count by language pair
Character count tracking
Error count by type

Logging

Structured JSON logs
Request/response tracking
Translation event logging
Error logging with context

🔄 Development Workflow

Local Development

cd backend/sema-api
pip install -r requirements.txt
uvicorn app.main:app --reload

Docker Development

docker build -t sema-api .
docker run -p 8000:8000 sema-api

Testing

Health check: GET /health
Documentation: GET /docs
Metrics: GET /metrics
Translation: POST /translate

🎯 Future Enhancements

Authentication Integration

Supabase JWT validation
User-based rate limiting
API key authentication

Scaling Considerations

Database integration for usage tracking
Redis caching for performance
Load balancer compatibility
Horizontal scaling support

Monitoring Enhancements

Grafana dashboards
Alerting rules
Performance profiling
Usage analytics

📝 Maintenance

Code Organization Benefits

Testability: Each component can be tested independently
Maintainability: Clear separation of concerns
Scalability: Easy to add new features and endpoints
Debugging: Structured logging and request tracking
Documentation: Self-documenting code structure

Adding New Features

New Endpoints: Add to api/v1/endpoints.py
Business Logic: Add to appropriate service in services/
Data Models: Add to models/schemas.py
Configuration: Add to core/config.py
Middleware: Add to middleware/

This architecture provides a solid foundation for a production-ready translation API that can scale and evolve with your needs.