For the auditing of the prices we provide, I will see if there is no security risk in sharing the exact code we use to make the api request to Coinbase/Binance so that anyone can use our code so that anyone can independently verify our prices.
We don't have any protection mechanism against flash crashes but the opposite is also true for any auto-cashout done with a short/long position which makes things fair in my opinion.
It's nice that you are open about the codes and make it public, I think having a stop-loss option is a better idea to avoid those flash crashes I'm curious maybe you could add like trading view graph wherein we can put indicators or other tools to analyze it or maybe that's too much since it will look like a trading website and not gambling site anymore?