Boyquotes/binanceWallet — reverse-engineered prompt

I want a tiny Node app that lets me see what is in my Binance wallet without opening the Binance site. It should read my Binance API key and secret from a .env file, connect to the Binance JSON API, pull my wallet balances, and save the results into a portfolio.json file that I can open later. The main goal is just to get the amount of crypto I hold for each asset in a simple readable format.

Please keep it very straightforward so I can clone it, run npm install, add my keys, run one command, and get the output file. A small README would help with setup, especially where to create the Binance API credentials and where to place them. If there are errors, show clear messages so I know whether my keys are missing or the API call failed. You can check the current Binance docs online if needed.