Some of the exchanges available through Tradewave provide support for native market orders. This means that an
order can be placed without a price specified; the exchange will attempt to match it immediately to the most
favourable order on the other side of the book.
In other cases (BTC-e, for example) the exchange doesn't provide the necessary order type, so the engine must
approximate a market order by fetching the order book and placing a limit order at the best price.
The downside of this is that market prices can change quite quickly. In the short amount of time between the
moment we receive the order book and when we place your order, the order book may have changed. To account for this,
we apply a short timeout to these orders and automatically adjust the price if they have not filled within a 20-second
window. This will happen up to a maximum of fifteen times; at that point, if your order hasn't filled, it will be
The tradewave "approximate market order" works very well and prevents the slippage that can occur by just buying into the book. I would like to be able to specify this instead of the "native market order" on the other exchanges. How can I do so?