What Flask Is and Why It Exists
Microframework, WSGI, and where Flask fits.
What Flask Is and Why It Exists is a free Flask Academy lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Flask Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Welcome to Flask
Flask is a tiny, friendly way to build websites and APIs in Python. You will go from zero to a running web app, one small step at a time. 🙂
A Web Framework
A web framework handles the boring plumbing of the web for you, so you write app logic instead of raw socket code.
Microframework
Flask is a microframework: it ships a small, sharp core and lets you add only the pieces your project actually needs.
Batteries Are Optional
Unlike heavier frameworks, Flask does not force a database or folder layout on you. You stay in full control of how your app is shaped.
What WSGI Means
WSGI is the standard contract between Python web apps and servers. Flask speaks WSGI, so many servers can run it unchanged.
Built on Werkzeug
Under the hood Flask leans on Werkzeug for request handling and routing, giving you a solid, well-tested foundation.
Templating with Jinja2
Flask pairs with Jinja2 to turn templates into HTML pages, so you can mix Python data into your markup later on.
Routes Map URLs to Code
The core idea: a route connects a URL like /hello to one Python function that builds the response. You will write these soon.
@app.route('/hello')
def hello():
return 'Hi there'Where Flask Fits
Flask shines for small services, prototypes, and APIs. It scales up too, but its simplicity is what makes it perfect for learning.
Flask vs Django
Django bundles everything by default; Flask hands you a blank slate. You choose tools as you grow, which keeps your first app light.
Python All the Way
Because Flask is pure Python, everything you already know about functions and dictionaries carries straight into your web app.
Quick Check
Quick check on what kind of framework Flask is.
Recap
Flask is a Python microframework built on Werkzeug and Jinja2, speaking WSGI. It is small, flexible, and perfect for your first web app. 🚀
Frequently asked questions
Is the “What Flask Is and Why It Exists” lesson free?
Yes — the full text of “What Flask Is and Why It Exists” is free to read here on the web, and the Flask Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Flask Academy course, upgrade to CoddyKit PRO.
What will I learn in “What Flask Is and Why It Exists”?
Microframework, WSGI, and where Flask fits. You practise Flask Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Flask Academy?
No prior experience is required. Flask Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “What Flask Is and Why It Exists” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Flask Academy lesson?
Yes. Every Flask Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- What Flask Is and Why It Exists
- Set Up a Virtualenv and Install Flask
- Hello World: Your First Flask App
- Run the Dev Server with Debug Mode