Not sure what kind of traffic they get, but httpbin.org uses it. Also this one site named Pinterest.
https://www.quora.com/What-challenges-has-Pinterest-encounte...
https://www.quora.com/What-is-the-technology-stack-behind-Pi...
> They started with Django but moved out of Django and currently use 'home grown framework on top of Flask'.
> Presently, the API does over 12 billion requests per day, all in Flask.
Wow, that is 138kqps. Not something that would strike me as your typical Python workload.
I don't know if it still is, but when I was at Mozilla the service that every instance of Firefox around the world hits to do the version/extension-compatibility checks was backed by Django, and was at something like 15k req/s served. Firefox has gained some market share in the four-ish years since I got that number, so probably larger now.