Common analytics bugs in network sniffers

When triggering tracking pixels on the click of buttons taking you to a new page you may encounter several issues. This happens because the browser will not give the tracking pixel enough time to contact the remote server. Is this affecting your actual data collection process? Here are a few examples of how a normal tracking pixel request should look like, to make sure everything is working correctly:

If you are not seeing something like the ones above, below is a list with the most common issues and the ones you need to pay attention to, as they probably indicate that there’s something wrong with your tagging.


These messages are often seen on tracking pixel requests with packet sniffers that sit on top of the browser, such as Tamper Data or HTTPFox .
This error occurs because the tracking pixel request is designed to let the browser proceed to the next page before waiting for a response from the data collection servers.
The serve’s response to the tracking pixel request is usually a blank 1×1 transparent image, which is not relevant to the content of the page.
If you see a line item in your packet monitor, either with a 200 OK response or an aborted response, the data has reached the data collection servers. There is no need to have the page wait any longer.
Be careful, network sniffers integrated as a browser plug-in rarely see the full response. They tend to see the request as aborted because the full response was not received. These monitors also rarely make a distinction between whether it was the request or the response that was aborted. Try using a standalone network sniffer for a more detailed view of the issue (like Charles or Fiddler)

Client closed connection before receiving entire response

When you using standalone sniffers, you may get a message in Charles saying “Client closed connection before receiving entire response.” This means the data reached the data collection servers, just the browser moved on to the next page before the 1×1 pixel was received.

Data request aborted

If an external packet sniffer is reporting that the data collection request is aborted, rather than the response, this is a cause for concern.


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