Introduction to Flask

What is Flask?

Flask is a lightweight WSGI web application framework written in Python. It is designed to make getting started quick and easy, with the ability to scale up to complex applications.

Created by Armin Ronacher of Pocoo, Flask is classified as a microframework because it does not require particular tools or libraries. It has no database abstraction layer, form validation, or any other components where pre-existing third-party libraries provide common functions.

Why Choose Flask?

Flask is More Powerful Than You Think

Despite its minimalist design, Flask is incredibly powerful and can be used to build complex web applications. Here's why Flask is more powerful than many developers initially assume:

• Scalability: Flask applications can scale from simple single-file scripts to large, complex applications with proper structuring.
• Ecosystem: The Flask ecosystem includes numerous extensions that add functionality without compromising the core's simplicity.
• Production-Ready: Many large companies and organizations use Flask in production, including LinkedIn, Netflix, and Reddit.
• RESTful Support: Flask makes it easy to build RESTful APIs with minimal overhead.
• Template Engine: Flask comes with the powerful Jinja2 template engine, making it easy to generate dynamic HTML.

Getting Started with Flask

Here's a simple example of a Flask application:

pip install Flask

from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello, World!'

if __name__ == '__main__':
    app.run(debug=True)

This simple application creates a web server that responds with "Hello, World!" when you visit the root URL.

Key Flask Concepts