We've had a user on IRC having trouble with large file uploads. Turns out waitress has its own internal max file upload max_request_body_size which defaults to 1G.

Waitress seems a bit less commonly used than other WSGI servers. I've had professional experience with gunicorn and uWSGI, but not waitress. All application servers have their own quirks, but I wonder whether gunicorn might be a better choice, simply because it's fairly commonly used.