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Introduction

Web apps are often created using a framework. Frameworks make it easier to develop web apps that are scalable, reliable and maintainable. It avoids recreating the same code over and over again. Common features are:

• URL Routing
• Output templates
• Database management
• Session management
• Security against common attacks

A framework may offer some or all of these features.

For example, the Flask web application framework does not have database support and you would need a separate module to use a database.  The Django web application framework supports databases by default.

Why use a web framework?

As you are doing web development, you want to avoid spending time on programming things that have already been solved. On the other hand, if you are an experienced web developer a web framework may not offer everything you need.

What Python web frameworks exist?

Django and Flask are the most popular web frameworks. However, you may want to evaluate the frameworks. An overview:

• Django
• Flask
• Bottle
• Pyramid
• Muffin
• CherryPy
• web2py
• Falcon
• Turbo2Gears

The most popular python web application framework is Django, followed by Flask.

# of projects on Github mentioning a framework.

Django

Django is the most used Python web framework. It takes care of many things so you can focus on the web app development. Sites built withDjango have dealt with high traffic spikes such as 50 thousands hits per second.  

Database access is achieved through an Object-relational mapper:   You define your data models in Python and Django deals with the actual database management systems (SQL).  However, if  you need to you can write your own SQL Queries with Django.  URL routing is supported by Django. It encourages beautiful URL design such as ending without .php or .asp.

Features:

• Object-relational mapper
• URLs routing and views
• Template engine
• Forms
• Authentication
• Admin
• Internationalization
• Security

If you want to know more about Django, read here.

Flask

Flask is a Python micro framework which is modular by design. The framework is intended to build web apps. Flask does not have a  specific database system or ORM system.  If you want to use a database, you'll have to use extensions. Flask is often combined with SQLAlchemy for database use.

Flask is very easy to get running, a minimal app would be:

from flask import Flask
app = Flask(__name__)
@app.route('/')
def hello_world():
    return 'Hello World!'
if __name__ == '__main__':
    app.run()

The framework supports URL routing, template (using Jinja2), session management and has some out of the box security.

Features:

• URL Routing and views
• Template engine
• Session management
• Logging

If you want to know more about Flask, read here.

Python Hosting

To run your app on the web, you will need hosting. Unless you want to do hosting yourself, you need a party to host. Hosting servers:

• PythonAnywhere.com
• Vultr VPS for Python