Ákos Kőműves I know that but here's the problem. localStorage is domain based. So when you switch to different tab for different website, your extension won't persist the session. There has to be an extension wide solution which is only (as far as i imagine) possible with chrome.storage.local Also, since you can't utilize localStorage, your background script can't use it for JS sdk. Service workers have their own runtime outside of window. If we want to have RLS active and use the database features, it's not possible extension-wide with the current session mechanism. I wonder how you would solve those problems? I ask because mainly those are the problems that I am trying to solve but there is no proper information anywhere in the internet :)