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.

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What is Python?

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.

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What web frameworks are available for Python?

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.

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The differences and similarities between Django and Flask

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.

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A direct comparison of Flask vs. Django

Features

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.

Security

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.

Flexibility

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.

Performance

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.

Learning curve

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.

Community

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.

Distribution

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.

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Python Flask vs. Django at a glance

  Flask Django
Scope Micro framework with many customization options Macro framework with many standard features
Security Secure, but depends on manual maintenance Secure
Flexibility Very flexible Less flexible
Performance Performs a little better in comparison Good performance, slower speed
Learning curve Simpler learning curve Steeper learning curve due to complexity
Community Large community Large community
Distribution Very popular Very popular

Pros and cons of Django and Flask

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

Flask

Pros Cons
✔ Slim ✘ Less support
✔ Quick learning successes ✘ Maintenance is more difficult
✔ Flexibility is unrivalled ✘ Dependence on third-party providers
✔ Fast framework  

Django

Pros Cons
✔ Many default functions ✘ Less flexible
✔ Very secure framework ✘ Not compatible with some plugins
✔ Compatible with plenty other frameworks ✘ Heavier
✔ Comprehensive admin tools ✘ Complicated learning curve
✔ Standard ORM  

When to use which Python framework?

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.

Flask vs. Django — the conclusion

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

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