Nonblocking IO

[intael]

This extension is a bit slow and after skimming through the code I think it's because you're using a synchronous http client (urllib). Have you considered using an asynchronous one and dispatching all the requests in a non-blocking manner? I can have a stab at it if you think it's something worth (I'd say it is, my spreadsheet with just 2 function calls takes a couple of seconds to open).