## TL;DR

Flask (Armin Ronacher, 2010) is a lightweight Python web framework — micro but extensible. Unlike Django's batteries-included, Flask starts minimal and grows via extensions (SQLAlchemy for ORM, Flask-Login for auth). Ideal for APIs, microservices, and prototypes.

## Core Explanation

Minimal app: `app = Flask(__name__); @app.route('/'); def hello(): return 'Hello'`. Jinja2 templating (shared with Django, different syntax). Blueprints: modular application components. Application factory pattern for scalable structure. Flask 3.0 (2023) added async support. Extensions: Flask-SQLAlchemy, Flask-Migrate (Alembic), Flask-RESTful.

## Further Reading

- [Flask Documentation](https://flask.palletsprojects.com/)