The GUI does it for you, it's in the bottom part labeled as "Balance" and the history is listed in the "history".
I don't get why you need to query your balance using a third-party client/explorer.
Thank you for this... I am trying to run an app that summarize my holding across multiple blockchains... therefore, instead of remembering many addresses for electrum (receiving and change addresses) I was wondering if I could somehow only have one for wallet...
I agree with you that the GUI does that for me, but I need to have a dashboard with BTC holding, ETH holding etc... I need to be able to get all the info from somewhere... so I was wondering, if I include one of the many Addresses of my wallet, somehow could I "get also the other addresses associated with the same wallet (read only)...
is it feasible?