flask

from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
  return "Hello world!" #if you want to render a .html file, 
                        # import render_template from flask and use 
                        #render_template("index.html") here.

if __name__ == '__main__':
    app.debug = True
    app.run() #go to http://localhost:5000/ to view the page.

from flask import Flask
app = Flask(__name__)

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

from flask import Flask, escape, request

app = Flask(__name__)

@app.route('/')
def hello():
    name = request.args.get("name", "World")
    return f'Hello, {escape(name)}!'

pip install -U Flask