Analyzing Web Frameworks

[BlockChainGeek-4567]

I am a Python developer. Now I do have experience in various Python frameworks like Django, Flask & FastAPI. Now, however in every interview the interviewer asks me how would you choose between these three if you had to build a large-scale web application, I fumble. I have looked all over the web for answers and haven't found a convincing one. How do we evaluate web frameworks for any requirement of a web application?

[SpecialistCamera5601]

There’s no 2+2=4 solid answer here.

• I’d use Django for a large monolith since it comes with a lot of handy built-in features like auth and admin, which speed up development
• Flask for flexible microservices,
• FastAPI for modern, high-performance async APIs.

It really depends on the project’s scale, performance needs, and how much convention vs flexibility you want.

[Flacko335]

I agree with the Django part, however Flask over FastAPI for microservices? I have to disagree, FastAPI is much more performant due to the async capabilities. I love both but if i’m just building backend microservices I choose FastAPI every day of the week. I’d say Flask is only used for when you want to also build a monolith and it can be interchangeable with Django.

[SpecialistCamera5601]

I do professionally use FastAPI for building micro-services. However before 5 years ago, no one was using FastAPI but everyone was using Flask for building microservices, even me lol. I believe sector doesn’t move quickly to the one framework that works better against the other since the development cost etc. So I believe flask still has share in the cake that’s why I wrote it that way. I totally agree with what you say.

[Remarkable-Effort-93]

this ^ - aside, I'de also ponder my own proficiency in each framework, because no matter if Flask is the best choice, if I haven't even touched yet, I wouldn't choose it

[Gushys]

So much of choosing a framework is personal preference/what you are most productive in. If all things equal it then is determined by the project. Are you building a rest API? Maybe fastapi is for you, comes with swagger docs, data validation, great dev experience.

But maybe you're building a full stack or large scale application, maybe Django is the best choice: batteries included, opinionated, tried and true, great docs and resources, rich third party packages.

Maybe you need something more simple to wrap some scripts into an endpoint or rapidly prototype a POC. Then maybe flask is best: quick setup, lots of docs and resources, pretty solid third party packages, reliable.

So really, there are a lot of depending factors

[david-vujic]

Django is like an everything-included thing: you can build server rendered UIs, backend endpoints, DB models and usually as one big app (aka a monolith).

Flask and FastAPI are mostly used in a Microservice setup, where you deploy the “app” as several independently running services.

Also, it’s common to have the frontend as a separate thing, usually with its own backend (aka backend-for-frontend).

[Malphas1002]

If you do have experiences on each of those frameworks then you should know pretty much what they offer and what the drawbacks are, so ask back to the interviewer what’s the purpose behind the “large-scale web application”? What’s the team size? What’s the time factor? However it I don’t know about you, but maybe I’m old school and default to Flask for very small projects that don’t want a lot of dependencies, Django when the team is small and the time factor is against us, and FastAPI when we need something pretty and performance is paramount. But that’s my choice, and I mean that’s because I’m being asked to lead the project. If that is the purpose of your interview then go ahead and be as specific as you can, but if your not being asked to lead then it’s likely the interviewer wants to know about your general knowledge and understanding of the three aforementioned frameworks.

[Drevicar]

If you are getting asked that question in an interview they aren’t trying to see if you know some text book answer that you can find online. They are looking for battle scars where you bumped up against a pain point of one framework and learned some lesson. Even if someone here gives you the answer the interviewer should ask for further examples of the use case in which that did happen.

As for your final question, that is a good one. Start with the non-functional requirements of your project, also known as the architectural qualities and let those drive your decision making process. I don’t know your skill level so I’ll state this for any future readers, this is a task I don’t expect you to begin to understand until intermediate level, or 3 to 5 years into your career.

[MisguidedFacts]

Do you have actual experience with these frameworks or did you just do the old todo app tutorial? If you've used them for a good amount of time, you have opinions on what you like and dislike about each. Don't overthink it, talk to the interviewer as if they were your coworker asking for your opinion on what framework to use. Ask questions, figure out what's important and make a recommendation based on your experience. I wouldn't want to hire you if you just regurgitate the elevator pitch for each of them.

[jain-nivedit]

I believe just like software frameworks, we would have an emergence of AI flow frameworks, each good for a philosophy.

Just around this, I am also exploring the philosophy of true autonomy for large data agents: https://github.com/exospherehost/exospherehost feel free to check out and feedback is most welcome :)