Did you implement this in your web server or within your application? I'd love to see the code if you're willing to share
https://github.com/progscrape/progscrape/blob/master/web/src...
Here's where we handle the rate limits:
https://github.com/progscrape/progscrape/blob/master/web/src...
I actually misremembered my implementation. It's rolling counting bloom filters, not a token bucket. :)