Heatmaps "behind the scenes"
These are the technical details about our heatmap analytics engine, for those who'd like to understand how it works on the "inside".
Most of the similar tools simply register mouse coordinates. This can be a problem since absolute coordinates can be misleading with fixed-width designs, liquid designs (100% width), right-aligned designs etc. So that's not how heattest works.
It's much more complicated
The next step is building the heatmap image. When you open the heatmap for viewing, the server creates an instance of a web-browser in memory, loads the page into the browser, and then restores the clicks coordinates by finding the clicked elements using XPath. This operation is VERY memory consuming and CPU demanding. And that's we have to rents number of cloud servers for this operation. Not to mention the heat map calculation itself, which is also a pretty tough algorithm for the server's CPU.