My personal experience with http is that you parse url and cookies by hand and never bother to use any crap “framework”. Of course, it has to be reverse-proxied with all irrelevant headers cleared, e.g. via nginx, which can also serve /static efficiently and provide https-http conversion. If you’re familiar with Lua, then writing http to json-only or binary-only unix socket is a no brainer in OpenResty, so you can skip backend-side parsing at all.

Flask/etc was useful magic only until I figured out what it really does between me and underlying socket.