Flask vs. Django03 Dec 2015
I really like Clojure. A lot. Since I’ve started using it seriously, I find myself going to it to solve most of my problems. My previous go-to language was Python. It has its share of issues (GIL, for example), but overall, it’s a joy to work in. Given its ease of use, it’s quite a popular language as well. As such, it’s pretty easy to find developers who know it, or are at least comfortable with it.
As much as I like Clojure, developer onboarding is a concern when starting a new project. Some friends approached me to help them with an idea they had. They’re both non-technical, so any decisions in this realm were left up to me. I would have loved to use Clojure, but finding people to help develop their app would be a little harder. So I found myself looking at Python again. Based off my previous experience, I found myself looking at two web frameworks to build the backend: Flask and Django.
I’m fairly familiar with Flask. I’ve used it to build big and small projects. I wasn’t particularly familiar with Django, so along with doing some tutorials/reading the documentation, I attended a few local Django meetups. The last one got cancelled, but I was supposed to give a talk comparing the two frameworks from my point of view. Since that meetup was cancelled, I’ve decided to write up a blog post instead. Note that this is all based off of my somewhat limited experience.
Flask is great. It’s a microframework written by Armin Ronacher. I personally love it. It’s incredibly flexible and easy to use. A basic app, as seen on the Flask homepage is as simple as this:
from flask import Flask app = Flask(__name__) @app.route("/") def hello(): return "Hello World!" if __name__ == "__main__": app.run()
This is a pretty straightforward example. You import the library, generate an app object, designate route handlers, etc. The API is very clean and easy to understand. For these reasons, I think Flask excels for small projects, but also for large ones (more on this shortly).
The double-edged sword of Flask is its unopinionated nature. For beginners, this presents a relatively small surface area that they need to learn. Flask handles routing, has a templating library, and not much else. When it comes to security, database integration, and other aspects that larger apps require, it’s up to the developer to determine what to use. Flask really doesn’t care. This is good if you know what you’re doing, but can be a bit intimidating if you’re new to development. It’s easy to make bad decisions due to inexperience.
Django takes a very different approach. It’s similar to Ruby on Rails - “batteries-included”. Pretty much everything is decided for you: the database ORM, routing, templating, etc. While this is great for getting an app up quickly, it’s not very flexible. Swapping components, or using Django in a way besides a monolithic app can present some challenges. That said, it does a great job of presenting a working development pattern.
The biggest downside is that, like Ruby on Rails, it requires the developers to learn a rather large system. You have to learn how to do things the “Django way”. Which isn’t necessarily a bad thing. It just means that you’ll generally have to focus on learning the system first, then building your app. No shortcuts. To make a point, the Flask example above tells you most of what you need to know. There is a short tutorial that goes through templating and some other features. Django is much more complicated, requiring a lengthy tutorial and likely some digging through documentation to understand all of what is going on.
Issues and Strengths
There are a few things surrounding the use of these frameworks worth mentioning. The Python2/Python3 divide is mostly resolved (you should probably use Python3 unless you have a specific reason not to). Django is very up-to-date with this. Since most of their components are specific to the Django ecosystem, they are all up-to-date and use Python3, assuming the version of Django you are using supports it.
In contrast, while Flask does support Python 3, it’s noted on the website that not all extensions do.
Django also provides long-term support (LTS) releases. If you’re using Django for a large application or simply in a large organization, these may be worth exploring for their stability.
Which should I use?
Both Flask and Django are great frameworks. Given their strengths and weaknesses, I’d recommend the following path for someone wishing to learn web development in Python.
First, learn Flask. It’s pretty small, and most people should be able to wrap their brain around it fairly quickly. Follow the tutorial. Then, build a small app. It could be a list making app, a Twitter bot, whatever.
Once you’ve done that, go and learn Django. Build something larger with it: maybe a CMS.
Finally, go back and learn how to build a similarly large application in Flask. This will require you to pick a number of libraries, understand how they fit together, their tradeoffs, etc.
It’s worth noting that these aren’t the only web frameworks available for Python. Far from it, actually. Explore all of the options.