Thank you, yes and indexed db too, as in other comment. I like to have exactly two API calls. -- load data (returns json) -- save data (sends json, returns 2

Thank you, yes and indexed db too, as in other comment. I like to have exactly two API calls. -- load data (returns json) -- save data (sends json, returns 200 ok) That is all! Let frontend bind everything to that json and save it every 1-2 seconds in setInterval.