Flask vs Django – Which Framework Should You Choose?

Python is a powerful language with an amazing set of tools to make life a lot less simple for python developers. But when it comes to web frameworks, Flask and Django are the most preferred ones. Web frameworks are collections of packages and modules that make it easier to write web applications, without focusing on the lower level details. These web frameworks have a lot of functionalities provided in them and help build elegant and powerful apps in a swift manner. Let us briefly look at these two frameworks, namely Flask and Django for a better understanding first and then move on to their comparison.

Flask
Flask is a free and open-source micro web framework that is written in the Python programming language to make scalable web applications with ease. “Micro” here does not mean that the framework is lacking functionality but rather means that the core is non-complex and extensible.  There are a few things that Flask does not contain like upload handling, ORMs (Object Relational Mappers), database abstraction layer, authentication, form validation, etc. but these functionalities can be integrated using pre-existing external libraries. The microframework is based on Werkzeug which is a toolkit for WSGI, i.e., Web Server Gateway Interface and Jinja which is a template engine for Python. Some well-known organizations that use Flask are Reddit, Netflix, Lyft, Airbnb, Uber, etc.
Django
Django is an open-source full-stack web framework as opposed to Flask and follows the Model Template View (MVC) style of architecture. Django helps to build better web applications with reusability features in less time and lesser code. It follows the Don’t Repeat Yourself principle and has a main focus on automating things as much as possible. It has dozens of functionalities like a lightweight web server for testing, form serialization, validation, caching framework, internal dispatcher amongst many others. Some companies which use Django are Udemy, Instagram, Quora, YouTube, etc. 
Flask v/s Django
Now let us look at their specific features and find out which one is better!Databases
Flask does not support the ORM framework and therefore the developers are free to choose the ORM that suits their application. Whereas, Django provides a powerful ORM and migration management tool which makes it easier to get started. Django supports a number of relational databases such as Oracle, MySQL, SQLite, MariaDB, and PostgreSQL. Flask not only supports relational databases but non-relational databases like MongoDB. ORM in Django makes it easy to create templates, views, forms, etc. which is made on data models but flask does not support data models. 
Size of the Project
If you’re going for a smaller web application then Flask will be an optimal choice since it is well suited for small and non-complicated web applications with high load. On the other hand, Django is a great choice for larger projects since it is designed for big, complicated and applications that deal with high traffic. As Flask is modular and highly flexible and you control and everything inside it, scaling it up can turn into error-prone and complex code. In Django, it is comparatively easy to scale up due to the fully-featured functionality it provides.
Performance
Flask will definitely outperform Django in performance and is significantly faster than Django due to the fact that it has lesser functionalities, fewer layers, and is a lightweight framework. Django provides a lot of functionalities that are not present in Flask for rapid development and hence has a performance downgrade as compared to its counterpart, Flask.
Security
Flask and Django provide similar mechanisms to prevent web application attacks and other threats. Django has an inbuilt system to prevent common attacks like Cross-Site Request Forgery (CSRF), Cross-Site Scripting (XSS), SQL injection, etc. This, in turn, helps to prevent or mitigate attacks that let an attacker carry out the execution of scripts in the browser, log in using the credentials of other users and execute arbitrary SQL code in the database. As Flask applications are much smaller, they are easier to secure since there is less area available to attack. But as Flask relies on external security extensions, it could mean that if the extension itself is compromised, this will result in the Flask web app being compromised. 
Routing System and Views
Routing is an important part of any web application and both these frameworks support routing and class-based views. It creates Universal Resource Locators (URLs) and then maps them to their respective functions which in turn determine what is to be done when the URL is loaded. In Django, URLs and views are defined in urls.py and views.py. To get access to the request object in Django, you will have to explicitly pass it, whereas, in Flask, the request object is global and therefore can be accessed easily.
Others
Django has a little ahead in popularity with a little more stars on its GitHub profile, as compared to Flask. But Flask has an exceptional fan base since it was released 5 years after Django was and was voted the most famous Python Web Framework for the year 2018. 
The documentation of Flask is extensive and very welcoming to beginners who want to set their hands on Flask. It involves a detailed explanation and covers everything from installation to deployment and has a lower learning curve than Django. Meanwhile, the documentation of Django is much more extensive than Flask since it is a full-stack framework and not a minimalist one. Also, there is a ready-to-use admin system that is not present in Flask. There are a few files in Django which are automatically present while starting a project and can be tough to comprehend for beginners. On the other hand, each and every line in the Flask project is written by you and you have full control of it from the beginning.
So what should you choose?
On comparing the two frameworks on different factors, it can be seen that both Flask and Django cannot be labeled as the best on a single feature. When Django is seen better for a larger project with rapid development and provides more features, Flask seems to be easier to start with. Both the frameworks are super useful for developing web applications and should be chosen depending on the current requirements and needs and the size of the project.