Learn FLASK with Real Code Examples
Updated Nov 25, 2025
Architecture
WSGI-based request/response handling
Routing via decorators
Extension-based modular design
Template rendering with Jinja2
Middleware support for pre/post request processing
Rendering Model
Client sends HTTP request -> Flask app
Route decorator maps URL to view function
View function processes request
Template renders response if needed
Response sent back to client
Architectural Patterns
WSGI-based request/response handling
Blueprints for modular routing
Extension-based modularity
Template rendering via Jinja2
Middleware-like hooks for request processing
Real World Architectures
REST APIs for web/mobile apps
Microservices backends
Authentication servers
Dynamic web dashboards
IoT data ingestion backends
Design Principles
Simplicity and minimalism
Flexibility and extensibility
Developer-friendly and easy to learn
Clear separation of concerns
Integration-friendly with Python ecosystem
Scalability Guide
Run multiple WSGI workers for load
Use caching layers
Load balance across instances
Use modular Blueprints for maintainability
Monitor performance and optimize queries
Migration Guide
Adapt from Django if moving to Flask
Reorganize views and routes as functions
Use extensions for missing features
Test routes and templates for compliance
Refactor large apps with Blueprints