# Gavin Andresen
# 2011-02-04 16:34:15
# https://bitcointalk.org/index.php?topic=3092.msg44430#msg44430

@s{quotedtext}
@s{quotedtext}
 @p{brk}
The fool-proof way of dealing with your use case (customer orders something, you want to ship after you're sure payment has cleared): @p{par}

+ Give each customer an account.  When they order, use getaccountaddress to get a bitcoin address to which they can send payment. @p{par}

+ Every N minutes ask bitcoin either the balance (with minimum 6 confirmations) for accounts with pending orders or all accounts @p{par}

+ If the account balance is enough to pay for the order, ship it and move the coins from the customer's account to a PAID account. @p{brk}
   If not... either wait or tell the customer they paid the wrong amount or maybe refund any extra they sent (you'll have to ask them for a refund address). @p{par}

The inelegant polling will eventually be fixed by bitcoin POSTing when new blocks or transactions arrive, but I think you'll still need to ask bitcoin what the account's current balance is@p{--} trust me, you really don't want to recreate all the bitcoin logic dealing with double-spent transactions or block chain reorganizations. @p{par}

If you grow to handling thousands of orders per day (which would be a very good problem to have) you'll want to buy or build a version of bitcoin optimized for high-volume transaction websites.  Or maybe you'll run 20 bitcoinds, each handling 1/20'th of the customers @p{--} I dunno, I don't spend a lot of time worrying about problems I'll have when my project is outrageously successful. @p{brk}