# Execution Options We allow two types of execution options for your order. ### **Post-Only** Post-Only is a condition that can be attached to your order to ensure that your order will be added to the order book as a maker order. In other words, it will only be executed if it does not immediately match with an existing order on the opposite side. If the execution conditions of a Post-Only order cannot be fulfilled, the order will be **fully cancelled**. This ensures that your order will always be added to the order book as a maker order (i.e. you will always be providing liquidity to the market). Post-Only orders cannot be used with the Good-Till-Cancelled Time-In-Force option as they are fundamentally incompatible. To enable the Post-Only condition, simply mark the 'Post-Only' checkbox in the order dialog. ### **Reduce-Only** Reduce-only is a condition that will ensure that your order will never increase your position size. This condition only applies to futures and perpetual markets. This condition can be used as a safeguard to avoid any unintended trades that may happen if the current position has already been closed manually, stopped out by other orders, or liquidated. By enabling this option, the contract quantity of your limit order will dynamically adjust downwards to match the contract size of the open position (minus other open orders), and will eventually cancel when reaching zero quantity. This effectively prevents any unintentional increase in your position. To enable the Reduce-Only condition, simply mark the 'Reduce-Only' checkbox in the order dialog.
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