I'm using the Facebook Graph and FQL API from an application (OAuth authenticated). I've been unable to find anything about rate limiting/throttling in the documentation. Normally, I'd expect some kind of limit in class/user...
Looking in at the Facebook app page Insigths -> Diagnostics:
PI Throttling
None during specified period.
API Throttling Warnings
None during specified period.
Feature Limits
Feature limit per user, per day
Requests 1.0 20
Which indicates some kind of throttling may be used. Anyone got more info on this?
Dont forget about the fql result set limit of 5000 results.
This is what is available as of right now:
600 requests per 600 secs per access token
And when your application gets more trusted like receiving likes, these limits are raised although this limit is already good enough for almost all the cases.
Other than the limits of API Calls, there is a limit to how many requests and invites you can sent to a user per day.
I don't really know any hard limits either, but for graph data requests, I have heard the number 600 queries every 600 seconds tossed around. However, this seems to be changing almost arbitrarily.
This seems to be the best info I could find on it. From personal experience, I have systems that make an average of 14-15 graph calls/min, and have been able to run them for days on end without error.