I am developing an application where the front-end does not talk directly to the blockchain. Back-end does that instead, due to some proccesses that can only be done in the back-end (file manipulation, for example). The idea is that users will "login" using metamask in the front-end and then back-end will handle all the communication with the blockchain in behavior of the user.
Since it's just a portfolio project, I am currently using a wallet of my own to cover the costs, with test ether in a testnet. But I know it's kinda ugly.
Question: is there a way to pop that metamask confirmation window to the user, whenever back-end performs a transaction? So that user's wallet will be charged, and not the "back-end's wallet".
I am currently using ethers.js, react in the front-end and nodejs in the back-end. I know it's odd, but if anyone has accomplished that, I would be really happy to hear how!