This looks like a duplicate of [Throttle violation after 300 calls][1] but this one is reported as fixed in 2012.

Today I made ~450 requests with an app key (no oauth token) and suddenly got a 502 response:

> throttle_violation : too many requests from this IP, more requests available in 86281 seconds"

Did I do something wrong? The same API key used to work some weeks ago and I made several thousand requests per day without getting any errors.

**Update:**

Most probably my fault but I'll need to wait another day to confirm it :)
I added backoff handling code also to the problematic requests and still failed. Then I noticed that the filter I use only includes .wrapper.total and backoff field is filtered out.

**Update 2:**

This is still happening after I started using a filter that adds the backOff and the quota_remaining properties.

I created a log file with every request that my app made and the responses. There is not a single backOff tag and the quota_remaining is not 0. 

File available [here][2]

After 644 requests I suddenly get a throttle violation error without any warning like backoff or something.

I'll create something like a unit test reproducing the issue but it would need some more time since I also need to wait for 24 hours again (or register a new API key but I don't want to abuse).

  [1]:http://stackapps.com/questions/2904/why-do-i-get-a-throttle-violation-after-300-requests-while-using-a-key-but-no-ac
  [2]: https://docs.google.com/document/d/1bvDYqY0EZmFRwm6tEjUSFSmfYShD2_23qjt-l1G27SA/pub