to open the “Quick Settings” sidebar.
Data Saver in Hermit works by asking the source server to send you a smaller page. Some sites respect that and send you a smaller page, and other sites completely ignore that. This is a fairly new protocol, so not many sites support it today, but it works for SSL as well as non-SSL (insecure web sites).
To be clear, Hermit does not intercept your Internet traffic or compress any data server-side. It only asks the server to send you a smaller page. If the server doesn’t support Data Saver mode, you will not see any benefits from it.
Want to read up on the technical details? Here you go: Delivering Fast and Light Applications with Save-Data
Hermit behaves exactly the same way as Chrome for SSL web sites. If you used Facebook or Twitter in Chrome, it would have consumed exactly as much data as Hermit, no more, no less, because they are both SSL by default. That is because Hermit uses the Chrome-based Android WebView component for rendering.
In addition to this, Chrome has a second Data Saver mode that is more aggressive, but only applies to non-secure web sites. For such sites, Chrome redirects all your Internet traffic through Google’s servers, which compress the pages and send them back to Chrome.
However, since so many sites today are encrypted, and more sites are being encrypted every day, the benefits of this approach are fast dwindling. Hermit does not support this mode, and does not send any of your Internet traffic to other servers.
There is an option in Hermit to turn off all images — that will really help you reduce the data you are using.