#Extensions

The Flask ecosystem provides numerous extensions:

• Flask-SQLAlchemy: Database ORM
• Flask-Migrate: Database migrations
• Flask-WTF: Forms and CSRF
• Flask-Login: User login
• Flask-Mail: Email sending
• Flask-Admin: Backend administration
• Flask-Caching: Caching
• Flask-CORS: Cross-origin resource sharing

Usage:

• Create extension instances in extensions.py
• Call init_app in the application factory create_app

Example:

# app/extensions.py
from flask_caching import Cache
cache = Cache(config={"CACHE_TYPE": "SimpleCache"})

# app/__init__.py
cache.init_app(app)

Custom Extensions: Implement the init_app(app) interface, read app.config as needed, and integrate with application lifecycle.