Getting Started with Flask

Published on March 28, 2025

Flask is a lightweight WSGI web application framework in Python. It is designed to make getting started quick and easy, with the ability to scale up to complex applications. It began as a simple wrapper around Werkzeug and Jinja and has become one of the most popular Python web application frameworks.

Why Choose Flask?

  1. Simplicity - Flask is easy to get started with as a beginner.
  2. Flexibility - Unlike other frameworks, Flask allows you to structure your application the way you want.
  3. Lightweight - Flask is lightweight and simple, yet powerful.
  4. Extensive Documentation - Flask has excellent documentation and a large community.

Creating Your First Flask Application

Let’s create a simple “Hello, World!” application:

from flask import Flask

app = Flask(__name__)

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

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

Save this to a file named app.py and run it with:

python app.py

Navigate to http://127.0.0.1:5000/ in your browser, and you should see “Hello, World!” displayed.

Adding Templates

Flask uses the Jinja2 template engine. Here’s how to render a template:

from flask import Flask, render_template

app = Flask(__name__)

@app.route('/')
def hello_world():
    return render_template('index.html', title='Home')

Create a folder named templates and inside it, create a file named index.html:

<!DOCTYPE html>
<html>
<head>
    <title>{{ title }}</title>
</head>
<body>
    <h1>Hello, World!</h1>
</body>
</html>

Conclusion

Flask is an excellent choice for both beginners and experienced developers. Its simplicity, flexibility, and powerful features make it perfect for a wide range of web applications, from simple websites to complex APIs.

In future posts, we’ll explore more advanced features of Flask, such as working with databases, user authentication, and deploying Flask applications to production.

Back to Blog