I'm playing around with their sandbox api and trying to figure out when a buy order will be rejected due to insufficient funds. It seems that market orders will be rejected only if you give the order funds greater than the amount of USD you have in your wallet. That seems straight forward enough. The case for limit orders seems a little bit more complicated. If I have $1000 in my wallet and I specify a buy order for 1 BTC for $1000 the order will be rejected due to insufficient funds. I'm guessing this is because I need money for any possible fees. However if the order goes on the order book as a maker order.
My question is do I need enough USD for possible fees regardless if the order becomes a maker or a taker order?