What is the query limit for Google's Suggest API?

Does anyone know the query 开发者_Go百科limit for this undocumented/unofficial google api?

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There doesn't appear to be a limit on the suggest api. I've made ~15,000 in the past hour without any disruptions.

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After 50.000th query I am getting 403 error response saying :

We're sorry... but your computer or network may be sending automated queries. To protect our users, we can't process your request right now.

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In my case afther ~100 queries google stops to give response i call it by json_decode(utf8_decode(file_get_contents('http://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl=pl-PL&q='.urlencode($keyword))),true);