There's not a simple answer, because there are multiple limits, but if you poll once every 30 sec you should be ok.

Thanks, I'll need to lower my rate limiter.

Cache your data and hit google instead of HN. That's the best way to solve this. Google can handle the traffic with considerable ease, HN is only one server that has a lot better things to do than to serve up multitudes of automated requests.

Btw, I like your API idea, it would be neat if HN had an 'official' one.

PG is quite responsive in email, maybe you could ask him directly about the maximum rate? I believe the search.yc guys do it once every 15 minutes or so.

Now this is great! I've requested such api, and so have many others, a few months ago. It somehow needs more publicity...