Maker vs taker: what is the difference
A maker order rests on the book and waits for someone to trade against it. A taker order trades against orders already on the book. The two pay different fee rates, and the maker rate is usually lower.
In the product
In ZML Trade, each leg’s order type sets its role. Market is a taker. Post-only only rests orders for normal opening and closing; risk reductions, automatic alignment and small-position cleanup still trade at market. Post-only, catch up at market rests orders and can catch up at market when the leg falls behind.
How to read it
A taker order fills at once, pays the taker fee and suffers slippage on a thin book. A maker order fills at its resting price and pays the maker fee. When the price moves away from it, it does not fill and the other leg waits. See Open and close with post-only orders.