Flask vs FastAPI vs Django: Choose the Best Python Framework

What are the backend options for Python?

Some people suggest starting with Flask as a backend option is a good way to start, then moving on with Pyramid, Fast API, Django in chronological order, and Other minimalistic frameworks like CherryPy. However, I think the use case or purpose should be clear when selecting either option, as each framework has its advantages and setbacks. So before picking up any framework in Python, the project scope and use case should be well known, including features to use, type of database, and its connector, scale of the project, etc. These factors will define which framework to proceed with. Tradeoffs should be balanced to select which framework to use. 

Here in this blog, we will explore the top 3 frameworks of Python, i.e., FastAPI, Flask, and Django. There are more frameworks like Pyramid or Bottle, but we will dive into the most often used and popular ones.  

As a Python development company, we guide you in starting with FastAPI and Flask, which are microframeworks, and then Django, which is a full-fledged framework bundled with a lot of stuff. So, what we mean by microframework is that these frameworks don’t come with tools like ORM, template engine, authentication, etc. Microframeworks are used to develop applications to build fast with minimal code, lightweight, and fast scaling, or to create microservices.  

A framework like Django inherently has an inbuilt ORM, forms, validations, template engines, and Middleware that handles authentication, sessions, security, etc. A proper folder structure needs to be followed.  

Regarding architectural structure, Django follows MVT, and fast API or Flask don’t necessarily follow any structure. Still, a folder structure similar to Django should be followed for better code management.     

1. Flask  

The lightweight Web Server Gateway Interface (WSGI) web application framework Flask is based on Python. It describes a standard interface for web servers and web applications.   

This framework, made available in 2010, is built on Werkzeug and Jinja2. REST applications are supported by Flask utilizing extensions like Flask-RESTful, Flask-RESTPlus, and Flask-Classful.   

Flask is also called a microweb framework since it does not require specific tools or libraries and attempts to keep the core simple but flexible. It solely offers development-related necessities, such as request handling, routing, etc.  

Pros:   

• When developing applications, Flask allows the developer independent or total control. You can play around with the framework's architecture and libraries.   
• Flask might be a Python-based, more compact system that doesn't require any external libraries or specialized instruments. It also uses expansions and lacks a database layer or plans for shape approval.   
• Flask's integrated unit testing approach allows for quicker debugging, reliable development, and experimentation freedom. It has a server and debugger built in.   

Cons:  

• Flask uses expansions instead of a database layer or mechanisms for shape approval. You need an ORM like Squelchy to conduct CRUD activities on a database or run raw SQL queries using any database connector or adapter.   
• There is no built-in bootstrapping utility for Flask.   
• Flask is solely appropriate for one-page apps.  

2. FastAPI  

FastAPI enables the development of quick web applications and Rest APIs in Python. The web framework, which supports Python 3.6 and later versions, was published in 2018.   

FastAPI is as quick and high performing as its name suggests. Leading businesses like Uber and Netflix already utilize the FastAPI architecture in their apps.   

You must use pip to install FastAPI and Uvicorn before you can begin using it. Asynchronous Server Gateway Interface (ASGI) server Unicorn is utilized in production.     

Pros:  

• FastAPI has the benefit of asynchronously processing queries. When declaring endpoints, all you have to do is place the async keyword before a function. Async def my_endpoint(), for instance.   
• Classes are prevented from being directly dependent on one another through dependency injection, a feature of FastAPI. This feature promotes code modularity, facilitating scaling while making code changes simple.   
• This web framework will report problems in JSON format after identifying improper data types. Data validation is done on the Pydantic library, greatly reducing errors during code writing.  

Cons:  

• FastAPI lacks an inbuilt security system but uses a fast API security module. Also doesn’t have inbuilt authentication and authorization as available in Django.  
• In FastAPI, everything is tied to its app. As a result, it's very easy for your main.py file to get extremely packed. This is a problem for users who are getting started with FastAPI. But there are workarounds to get with this too.  
• Since FastAPI is a relatively new framework, its community is still small but growing quickly.  

3. Django   

Django is a Python-based open-source framework for designing web applications created in 2003. With its batteries-included approach, Django is a full-stack web framework that makes applications ready to use. 

Create effective web applications more quickly using less code.  

The Django project is set up, has excellent online support, and is well documented.   

Numerous major corporations utilize Django, including Instagram, Coursera, Mozilla, Pinterest, National Geographic, Spotify, Udemy, and YouTube.  

Pros:  

• The key features of Django are Admin Interface, Database ORM, and Built-in template engine. These three tools come in Django inbuild. These tools are not inheritably coming with Flask or FastAPI.  
• Django is a free and open-source system built on Python that is modeled around the MVC (model-view-controller) method of structural design. 
• Django is adaptable to JSON, HTML, XML, and many more formats.  
• Django guarantees security with powerful authentication systems and protocols to avoid clickjacking, unauthorized access, cyberattacks, etc.  
• Django is suitable for multi-page applications.   
• Advanced topics like Signals (similar to triggers in SQL), channels (deals with WebSocket), and celery (async job queue) are also supported in Django.  

Cons:  

• It's based on monolithic architecture, making things too complicated and difficult to fix.  
• Everything is based on Django ORM.  
• Django doesn't include REST support, though DRF can be installed separately to get REST support.  
• There are too many functions and a high-end framework for an easy project. Hence, the Codebase size is relatively larger.  
• Learning Curve for this framework is steep.  

Framework	Features	Strengths	Weaknesses
Flask	Lightweight, easy to learn	Simple, flexible, quick to develop	Limited features, not well-suited for large or complex projects
Django	Full-stack, includes features for both frontend and backend	Powerful, scalable, well-documented	Can be complex to learn, not as fast as other frameworks
FastAPI	Fast, efficient, based on ASGI protocol	Fast, efficient, well-suited for asynchronous applications	Newer framework, not as well-documented as other frameworks

Conclusion:  

So, using which framework isn't about how powerful it can be; rather, it should be picked based on one’s specific requirements. E.g., If we need to create APIs rapidly without too many security concerns, then FastAPI may be an option to proceed with. If one needs admin panel support and needs to deal with DB in more of a Python way and should be secure, then one should go with Django. If a one-page small-scale web application needs to be built, then Flask is the quickest solution.  

Also, read: A Minimalist Python Framework: CherryPy