As I wrote in the last blogpost that keeping the traffic/bandwidth usage low is very important, I know want to explain how we achieve it.
Keeping it stupid and simple is often more complicated than building a big overloaded code.
2. CDN and Caching
The best thing to keep the traffic usage low is to don't transfer any data and that's exactly what we try to achieve. As I wrote in the first blogpost the data what our script transfers is no image data, it's the structure of the website. This allows us to check if we already have transferred the website. We do this by calculating an hash of some specific data/points of the website which ensures that the structure and the content matches. Afterwards which check this hashcode serverside if the hash is already there (only your tenant). As you might think it wouldn't make a lot of sense to simply calculate an hash of the whole structure, because then we would always get a different hashcode and the data is always transferred. You're right, because the structure of most of the websites differs in small areas which are mostly not visible for the user. Therefore we only check specific points/data which allows us a high match rate for the hashes and ensures that the hashcode is always different if the content for the user differs.
If a hashcode matches, we only transfer the following user activities.
Especially for static websites, our hashcode algorithm works pretty well.