What's the requests/second standard for scraping websites?

Posted by feydr on Stack Overflow See other posts from Stack Overflow or by feydr
Published on 2010-05-29T22:24:43Z Indexed on 2010/05/29 22:32 UTC
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screen-scraping

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etiquette

This was the closest question to my question and it wasn't really answered very well imo:

http://stackoverflow.com/questions/2022030/web-scraping-etiquette

I'm looking for the answer to #1:

How many requests/second should you be doing to scrape?

Right now I pull from a queue of links. Every site that gets scraped has it's own thread and sleeps for 1 second in between requests. I ask for gzip compression to save bandwidth.

Are there standards for this? Surely all the big search engines have some set of guidelines they follow in regards to this.

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