System Architecture Overview

The Personal Finance Platform follows a modular, service-oriented architecture built on Django with Celery for asynchronous processing.

High-Level Architecture 

┌─────────────────────────────────────────────────────────────────┐
│                        Presentation Layer                       │
├─────────────────────────────────────────────────────────────────┤
│ Django Templates │ REST API │ WebSocket │ Static Assets         │
│                  │ (DRF)    │ (Channels)│                       │
└─────────────────────────────────────────────────────────────────┘
                                    │
┌─────────────────────────────────────────────────────────────────┐
│                       Application Layer                         │
├─────────────────────────────────────────────────────────────────┤
│ Analytics │ Backtesting │ Tax │ Realtime │ Visualization       │
│ Services  │ Engine      │ Calc│ Feeds    │ Dashboards          │
└─────────────────────────────────────────────────────────────────┘
                                    │
┌─────────────────────────────────────────────────────────────────┐
│                         Domain Layer                            │
├─────────────────────────────────────────────────────────────────┤
│ Portfolio │ Assets │ Users │ Transactions │ Data Sources       │
│ Models    │ Models │ Models│ Models       │ Adapters            │
└─────────────────────────────────────────────────────────────────┘
                                    │
┌─────────────────────────────────────────────────────────────────┐
│                      Infrastructure Layer                       │
├─────────────────────────────────────────────────────────────────┤
│ PostgreSQL │ Redis │ Celery │ File Storage │ External APIs     │
│ Database   │ Cache │ Worker │              │ (Yahoo Finance)    │
└─────────────────────────────────────────────────────────────────┘

Core Components 

Django Application Structure 

The application is organized into focused Django apps:

personal_finance/
├── analytics/          # Portfolio analytics and metrics
├── assets/             # Asset management and price data
├── backtesting/        # Strategy simulation engine
├── contrib/            # Third-party integrations
├── data_profiler/      # Data validation and profiling
├── data_sources/       # Market data adapters
├── portfolios/         # Portfolio and position management
├── realtime/           # WebSocket streaming services
├── tax/                # Tax calculation and reporting
├── users/              # User management and authentication
└── visualization/      # Charting and dashboard services

Configuration and Routing 

config/
├── settings/           # Environment-specific settings
│   ├── base.py         # Common settings
│   ├── local.py        # Development settings
│   ├── production.py   # Production settings
│   └── test.py         # Testing settings
├── urls.py             # Main URL routing
├── api_router.py       # API endpoint routing
├── asgi.py             # ASGI application (WebSockets)
├── wsgi.py             # WSGI application (traditional HTTP)
└── celery_app.py       # Celery configuration

Data Flow Architecture 

Request Processing Flow 

HTTP Requests: Routed through Django’s URL dispatcher
API Requests: Handled by Django REST Framework serializers/viewsets
WebSocket Connections: Managed by Django Channels consumers
Background Tasks: Queued via Celery for asynchronous processing

Data Processing Pipeline 

Service Layer Pattern 

Each domain module follows a consistent service layer pattern:

# Example: Analytics Service Structure
analytics/
├── __init__.py
├── models.py           # Data models
├── services.py         # Business logic services
├── serializers.py      # API serialization
├── views.py            # HTTP request handlers
├── consumers.py        # WebSocket consumers
├── tasks.py            # Celery background tasks
├── admin.py            # Django admin integration
└── tests/              # Test suite

Service Interfaces 

All services implement consistent interfaces:

class BaseService:
    """Base service class with common patterns."""

    def __init__(self, user=None):
        self.user = user

    def validate_permissions(self, obj):
        """Check user permissions for object access."""
        pass

    def get_queryset(self):
        """Return filtered queryset for user."""
        pass

Background Processing 

Celery Task Architecture 

Background Tasks:
├── Data Ingestion Tasks
│   ├── fetch_market_data.py
│   ├── update_asset_prices.py
│   └── import_transactions.py
├── Analytics Tasks
│   ├── calculate_portfolio_metrics.py
│   ├── generate_performance_reports.py
│   └── update_risk_metrics.py
├── Tax Processing Tasks
│   ├── calculate_capital_gains.py
│   ├── identify_tax_lots.py
│   └── generate_tax_reports.py
└── Maintenance Tasks
    ├── cleanup_old_data.py
    ├── backup_database.py
    └── system_health_checks.py

Task Queue Strategy 

High Priority: Real-time price updates, user-initiated calculations
Normal Priority: Scheduled analytics, report generation
Low Priority: Data cleanup, system maintenance

Security Architecture 

Authentication & Authorization 

Session-based Authentication: For web interface
Token Authentication: For API access
Permission Framework: Django’s built-in permissions with custom extensions

Data Protection Layers 

Input Validation: All user inputs validated at API boundary
SQL Injection Protection: Django ORM with parameterized queries
CSRF Protection: Django’s CSRF middleware
XSS Protection: Context-aware output encoding
Sensitive Data Handling: Encrypted storage for API keys

Scalability Considerations 

Horizontal Scaling Points 

Web Servers: Multiple Django instances behind load balancer
Background Workers: Multiple Celery worker processes
Database: Read replicas for analytics queries
Cache Layer: Redis cluster for session and data caching

Performance Optimizations 

Database Indexing: Strategic indexes on high-frequency queries
Query Optimization: Use of select_related and prefetch_related
Caching Strategy: Multi-level caching (Redis, Django cache framework)
Static Assets: CDN delivery for CSS/JS/images

Monitoring & Observability 

Health Check Endpoints 

/health/ - Basic application health
/health/database/ - Database connectivity
/health/cache/ - Redis connectivity
/health/celery/ - Background worker status

Logging Architecture 

Logging Hierarchy:
├── Application Logs
│   ├── personal_finance.analytics
│   ├── personal_finance.backtesting
│   └── personal_finance.realtime
├── Infrastructure Logs
│   ├── django.db.backends
│   ├── celery.worker
│   └── channels.consumer
└── Security Logs
    ├── django.security
    └── personal_finance.auth

Deployment Architecture 

Production Topology 

Production Environment:
├── Load Balancer (Nginx)
├── Application Servers (Django + Gunicorn)
├── Background Workers (Celery)
├── Message Broker (Redis)
├── Database (PostgreSQL)
├── File Storage (Local/S3)
└── Monitoring (Logs + Metrics)

Container Strategy 

Application Container: Django app with Gunicorn
Worker Container: Celery workers
Database Container: PostgreSQL with persistent volumes
Cache Container: Redis for sessions and caching