The recommendation with Bitcoin is to wait for six confirmations before considering a transaction secure. That's about an hour, best case. It might be overly se

The recommendation with Bitcoin is to wait for six confirmations before considering a transaction secure. That's about an hour, best case. It might be overly secure for most applications, but that's generally what people use. Other PoW-based systems have similar recommendations. You can have more frequent blocks, but the economic security offered by each confirmation will be lower. There are other nifty networks called payment networks which promises instantly secure transactions, the most well known being Lightning. They offer that by identifying cheating and offering both parties to get their money out in case the other party does. They are still pretty experimental but the results are promising.