This was a financial function which calculated an internal return of return for a long series of uneven cash flows, essentially a python implementation of the XIRR function that spreadsheets have.

To get to the required two decimal places of precision, each call would recurse 50-60 or more times so this was more or less all that the server was doing.

A VERY low hanging fruit.

What's interesting is also how go and python interaction is since you seem to be able to call go from python and the reverse very efficiently.

Sorry but we actually cheated on that part. Redid the page so that the function that is now in Go is a separate little service that is called via ajax directly by the users' browsers.

So there's no actual Python-Go interaction in our code.

This was quicker, cleaner and has made the page more responsive for users.

Thanks this comment is useful, client side integration is integration after all, and I think if it was simple, you would have it done differently (if I understand your words correctly - "cheating").