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Sensor Log

Root Cause Analysis

AlertFox error reports include detailed information to diagnose and fix website uptime and performance problems. The Sensor log report include detailed information about a sensor. This helps diagnose and fix website up time and performance problems. Each error message contains in-depth information on the error, down to each byte that was sent and received before the problem. It is also possible to export this data to CSV file for further analysis.




Browser Screenshots [SCR]

In case of an error, clicking on SCR shows the actual screenshot of the test browser at the time of the issue. Note, that this functionality is only applicable to iMacros sensors.

Performance Profiler [PERF]

Interested in how fast each step of your transaction (macro) sensors is performed by the browser instance you selected? Then have a look at the performance logs, marked as [PERF] in your log. Note, that this functionality is only applicable to iMacros sensors.




Waterfall Charts [WF]
In order to get a grip on the load time of each and every element of your site, Alertfox allows you to make use of its feature – Waterfall charts. This feature can be enabled by checking the option “Show Waterfall charts on Error” under Advanced settings of a sensor settings. Enabling this option creates HAR (HTTP Archives) files that show the complete HTTP traffic. Similar to SCR and PERF, sensors that have Waterfall charts enabled would be able to a new entry WF ,that stands for Waterfall charts.



Technical details behind HAR files

A typical Waterfall chart (in the form of HAR files) is shown below.



Each bar on the diagram display timings of each HTTP transaction going from and coming back to your server. e.g. When you are loading “” your browser will have a conversation with a web server using the HTTP protocol. What HAR displays, is the exchange, between the server and the client web browser, and the timings involved in doing so. Pointing your browser to, every element the page has to be downloaded one at a time. This may include text, image, scripts, and any other content the browser is using to render the page. To do so, the browser is sending requests to the server, which in return replies and delivers the content it has been asked for. HAR files describe that negotiation and exchange, as well as how much time goes by doing so. Any error or missing content will also be visible on your HAR report / waterfall. Using this information, both the diagnosis and timings, will help a web admin fix errors & enhance the overall page loading time. Waterfall charts in the form of HAR files can also be useful to power users that would need a diagnostic tool at the HTTP level.