Am planning to use iTunes Search API to get App related information - http://www.apple.com/itunes/affiliates/resources/documentation/itunes-store-web-service-search-api.html
Wanted to know if there is any pre-defined Rate/Throttle Limit on the API usage. Couldn't find any info related to this in their Documentation / Stack / Google.
Does anyone have info on this?
On
I don't know what the exact rate limit is and couldn't find any info on this from Apple. But I can assure you that there must be a rate limit somehow since most of my requests on my server don't succeed, they result to an HTTP Status 403. The exact same requests work on other computers and sometime later (on retries) on the same server.
I have tried to find the limits by making a lot of requests concurrently on my development computer but no requests lead to the same error as on my server. My server makes several dozen thousands of requests per day at the moment (I'm fetching all links once for caching those) which leads to more than 90 % of the requests to fail – but some succeed.
Therefore I did as suggested by Ted Hosmann an contacted Apple for access to the EPF files. If you don't exceed more than – say – a dozen thousand of requests per day, I guess the rate limit shouldn't be a problem for you. That's the number of requests I tried on my computer concurrently without any problems. If you need more, you should use the iTunes Enterprise Partner Feed as well.
On
If you are looking for a large amount of records, it might be easier to download the EPF file first - then supplement your updates using the lookup API:
https://affiliate.itunes.apple.com/resources/documentation/itunes-enterprise-partner-feed/
If you hit the Search or Lookup API aggressively, you may start to experience longer response times, greater than 30 seconds or failed responses.
Answering the original question:
This is from iTunes Search API Documentation