7 Ways to Limit API Use

John Musser
Feb. 15 2006, 01:01AM EST

Nearly all API providers place some sort of usage limits on their APIs. While not getting into the reasons why they do this -- be it controlling costs, preventing abuse or other -- it wasn't until this week while updating the API database that I realized just how many ways this can be done. Here's a sampling that shows the types and some representative examples:

  • Time based limits: 1 call per second (Last.fm)
  • Call Volume by Address: 5,000 queries per IP per day (Yahoo! Image Search)
  • Call volume per-application: 10,000 queries per application per day (MSN Search)
  • Return results volume: 10 results per query (Google Search), 100 items returned per call (Tailrank), 100 blogs per map (FeedMap)
  • Data Transmission Volume: 120 packets of 1.6KB per minute (MSN Messenger)
  • Formula: Monthly quotas based on various factors (Google AdWords)
  • Kindness of strangers: "Please be gentle with Simpy's server" (Simpy)

The above can, and are, used in combination. And there's probably more ways than these. Of course arrangements can be made with API providers to work around these limits. But that's a different discussion. Maybe one for MashupCamp.

John Musser




Sounds good Chris. The Business Models in Mashups should be one of the more interesting sessions. Actually, I'll bet it'll probably be more of an 'ongoing theme' of the event...

Good. Another question, when I look through the API list, I find most of them are providing APIs through SOAP WS, REST, RSS, or javascript, is it possible to have a summary of the ways that Web20 apps provide APIs and how each kind of APIs is consumed?



Haiqi, yes, summary statistics on how APIs are provided are coming soon. Getting specifics on how they are consumed will be more difficult as not all API providers disclose those sorts of details. At least as far as I'm aware.

[...] The vast majority of the over 400 open APIs listed here have imposed some limitations on how much they can be used, certainly in the free use model. There are good reasons for this ranging from preventing abuse, controlling costs, or other business-driven reasons. Just over a year ago, in 7 ways to limit API use we looked at some of these. With twice as many APIs now listed it’s a good time to check back and see what other ways APIs get throttled. As a refresher, here’s the original list: [...]