That's a cool idea. I wanted to make a coin tracker that didn't require API keys to be sent to the server. I started building it all browser based.
Used a local config file to store API keys and used ccxt to query the exchanges via AJAX so it never touched the server.
Problem is most of the big exchanges i tested don't allow browser originated queries (CORS) on authenticated calls. Too bad.
https://developers.coinbase.com/docs/merchants/technical-faq#ajax
Good luck with your project.