Tools like CoinStats are able to generate an historical graph of the portfolio balance.
I would like to do the same but I didn’t see any endpoint in the Binance API that allows to get the portfolio balance over time?
How can I achieve the same result using the Binance API? Or maybe they’re using a non-public endpoint?
There is no endpoint that would return your historical balance. It’s best to keep track of your balance on the client side. You can use the API to get historical prices though.
It should be possible to reconstruct the balance by querying your trade/deposit/withdrawal history and backtracking from your current balance. However, it’s not straightforward and the APIs only return limited history.