Python Flask Get Started


Flask is simple WebFramework for Python.
Different from Django, the feature is simple. But it becomes more and more popular.


If you have pip, just simple

pip3 install Flask

First Simple Application

To create project, Flask doesn’t have any command.
Create project folder by myself and make python file

from flask import Flask

app = Flask(__name__)

def hello_world():
    return 'Hello World!'

if __name__== '__main__':

Create simple routing and application run code.
To start this web application run python


This application runs with http://localhost:5000

Debug Mode

Debug mode is helper for debug application.
To add one line, we can test without stop and run.
This plays auto reload

app = Flask(__name__)
app.debug = True    # Debug mode on