Flask vs. Django — a com­par­is­on of the Python frame­works

Django and Flask are among the most popular web frame­works available for Python. While Flask has a light­weight structure, Django boasts many functions.

Python is a universal pro­gram­ming language published in 1991. Its goal is to use shorter and more readable code. Today, the dynamic language is managed by the non-profit Python Software Found­a­tion (PSF) and continues to be developed by a large and active community. Despite its simple syntax, Python is suitable for extensive software projects. You can find out more about the pro­gram­ming language in our Python tutorial.

A vast number of Python web frame­works are available besides Django and Flask. They tend to differ in their objective, their structure, and/or primary focus. For example, full-stack frame­works contain toolboxes for apps and other software, but as a result they’re much larger. Prominent examples are Tur­boGears and Giotto.

Other providers rely on non-full-stack solutions. These focus on the basics for maximum freedom when de­vel­op­ing new ap­plic­a­tions. However, this means users are having to do a lot more work them­selves. Well-known examples include CherryPy or Growler.

Both Django and Flask are free and open source and have an en­thu­si­ast­ic following worldwide.

Django was developed in 2005 and is a cross-platform full-stack framework with BSD license. Ori­gin­ally conceived as Django CMS, it’s now suitable for a variety of different web ap­plic­a­tions. Django follows the DRY principle (“Don’t repeat yourself”) and offers an all-round solution for building and main­tain­ing websites or other web de­vel­op­ments. Being a reliable and well-doc­u­mented framework, Django is used by Instagram, Spotify, and YouTube, among others.

In contrast to Django, the micro-framework Flask by Austrian developer Armin Ronacher released in 2010 takes a min­im­al­ist approach. It doesn’t include much more than a library “tool” for the creation of WSGI ap­plic­a­tions and the template engine Jinja. Flask doesn’t provide any other com­pon­ents. However, de­velopers can easily integrate existing libraries and add numerous features, while retaining a slim core in Flask. The framework has a free BSD license and is used by Netflix, Reddit and Airbnb, among others.

When it comes to features the dif­fer­ence between Flask and Django is im­me­di­ately apparent. While Django has numerous features, Flask is a sparse framework. However, the latter can provide most of the required functions ex­tern­ally. Django includes a standard ORM and supports e.g. MySQLi and Post­gr­eSQL. The framework can be applied to almost all web formats and works in com­bin­a­tion with other client-side frame­works. Flask forgoes an ORM and relies on features from other libraries.

Django and Flask are both con­sidered secure solutions for different reasons. Django boasts multiple security features such as CSRF, SQL and XSS and is supported by an engaged team identi­fy­ing bugs and errors. Many other security-relevant features are added and performed auto­mat­ic­ally.

The same is not the case for Flask. Because of its compact code, there are fewer security risks to begin with. Security issues are more likely to arise when adding third-party ex­ten­sions. Flask is secure if you keep track of required updates and keep libraries updated. Unlike Django, Flask doesn’t offer automatic updates. Main­tain­ing the security of ap­plic­a­tions and avoiding classic Python errors requires sig­ni­fic­antly more effort compared to Django.

Flask is fully flexible. The web framework provides the base and lets you add libraries as you need them. Some prior knowledge is required to design in­di­vidu­al projects. Plugins and ad­di­tion­al features can be used as you see fit. While this is tempting, it also requires more work and knowledge. Unlike Flask, Django steps are pre­defined to some degree, and not all third-party plugins are suitable. This means the macro framework is a bit less flexible, but also more user-friendly.

The two frame­works differ widely when it comes to per­form­ance. In a su­per­fi­cial com­par­is­on, Flask comes out ahead of Django, primarily because it’s lighter and faster. Django can be sluggish at times. However, per­form­ance changes as you add more features and plugins to Flask as these can reduce speed so that the two end up per­form­ing similarly.

Flask is a bit easier to learn in part because the framework is smaller and therefore easier to use. Django has a steeper learning curve as it takes time to in­tern­al­ize the structure and special features. However, once you’re familiar with Django, many of its processes can be automated. Comparing Flask vs. Django, the use of plugins in the lighter opponent may well involve some pitfalls. If you’re still trialing the frame­works, it’s a good idea to begin with Flask and then move onto Django.

Whether you’re only just beginning work on a web framework or you’ve already managed several suc­cess­ful projects, doc­u­ment­a­tion and an active user community are in­dis­pens­able to help with errors and issues. Both, Django and Flask are exemplary here. There are plenty of helpful user cases and support provided by their large user com­munit­ies.

Given the vast pos­sib­il­it­ies and con­vin­cing security ar­chi­tec­ture, Django and Flask are both widely used. Even large companies rely on the qualities of the two frame­works.

To make the right choice, it’s worth looking at the pros and cons of Flask vs. Django:

Since both frame­works have their strengths and weak­nesses, it’s a good idea to check your project needs. For example, Django is the right choice when embarking on a large, extensive project, possibly even col­lab­or­at­ing with other de­velopers. It’s a safe and func­tion­al solution. For smaller projects, beginners and sites with changing needs, Flask is a better option. Its flex­ib­il­ity makes the framework a powerful al­tern­at­ive for beginners and pro­fes­sion­als alike.

There’s no clear winner in our com­par­is­on since Django and Flask are ul­ti­mately very different frame­works. If you’ve chosen to work with Python vs. PHP, it’s worth testing both framework and using them in a project-dependent manner