What is ‘WSGI’ & ‘ASGI’? — Exploring their Key Differences

Short & precise description of the 2 Python web server interfaces, their framework differences & use cases.

image by author

Before we understand WSGI & ASGI, please note that — Web frameworks such as Flask & Django can be used with either WSGI or ASGI, but by default, they don’t have inbuilt support for asynchronous programming.

To use Flask with ASGI, you will need to use a third-party library such as gunicorn whereas for Django, you will need a library such as uvicorn.

WSGI

WSGI stands for Web Server Gateway Interface. A ‘WSGI’ is a type of interface that sits between the server and the client. This interface dictates the method of data exchange between the client & the server.

WSGI is older & is very widely used by a lot of companies & applications. Some examples are —

• Reddit
• Instagram
• Spotify
• Airbnb

Key points about WSGI —

• Synchronous: WSGI is synchronous in nature, meaning that an application will need to process the current request before accepting a new one. This leads to a longer processing time when handling multiple requests at once. (This can, however, be mitigated to an extent with the help of workers!)
• No Asynchronous Programming Support: WSGI does not provide in-built support for asynchronous programming which can be a problem if one is used to writing asynchronous code.
• Widely Adopted: WSGI has one big advantage over ASGI, which is its wide adoption. WSGI is a mature server interface and has seen usage across many major platforms & applications.

ASGI

ASGI stands for Asynchronous Gateway Interface. An ‘ASGI’ is again, a type of interface that sits between the server and the client. This interface dictates the method of data exchange between the client & the server.

Unlike WSGI, ASGI is not very old & is also very widely used by a lot of websites & applications. Some applications & technologies that use ASGI—

• Discord
• Twitch
• Next.js

Key points about ASGI —

• Asynchronous: ASGI is asynchronous in nature, meaning that an application doesn’t need to process one request before accepting a new one. It can accept multiple requests at the same time & work on them parallelly. This leads to a shorter processing time when handling multiple requests at once.
• Asynchronous Programming Support: An Asynchronous interface supports & encourages an asynchronous programming paradigm.
• Less Adopted: ASGI might have a small drawback compared to WSGI, which is its lower adoption rate.

This was a short summary of what is WSGI & ASGI & what are their key attributes. I know the post was very short, hence there will be a follow-up article on why you should switch to an ASGI framework, so stay tuned & thanks for reading! 🖤

Check out these other awesome posts —

Most Asked Interview Questions in Python/Django

Essential Things you should be able to do using Pandas✨

In Plain English

Thank you for being a part of our community! Before you go:

• Be sure to clap and follow the writer! 👏
• You can find even more content at PlainEnglish.io 🚀
• Sign up for our free weekly newsletter. 🗞️
• Follow us on Twitter, LinkedIn, YouTube, and Discord.