Order Types, Expiry, Maker & Taker

Polymarket uses a central limit order book, often called the CLOB. You sign an order with a price, size, side, and order behavior. If your order can match existing liquidity, it trades. If it cannot, a limit-style order can rest on the book until another trader matches it, you cancel it, or it expires.

This is the default behavior for most Polycopy copy-trading flows. Polycopy places a limit order on Polymarket at your protected price and lets it rest until it expires. On a Trader Bot the default is 4 minutes, and it is a per-bot setting you can change. On a manual trade you pick the expiry yourself in Settings under Trading. If another order matches during that window, it fills; if not, it expires on its own. Resting rather than crossing the spread can improve the price, at the cost of an order that may never fill. Shorter is not a compromise: resting-fill quality gets worse the longer an order sits, and most resting fills land in the first minute.

Fill and Kill tries to trade immediately against available orders on the book. It fills whatever size is available at your limit price or better, then cancels the unfilled remainder. This is useful when you want quick execution and do not want a stale order sitting open, but you may get a partial fill or no fill if liquidity is thin.

Fill or Kill is stricter than FAK. The whole order must fill immediately at your limit price or better, or the entire order cancels. It avoids partial positions, but it is easier to miss trades in thin or fast markets because one missing share can cause the full order to fail.

Polymarket also supports Good 'Til Cancelled limit orders. A GTC order stays open until it fills or you cancel it. A GTD order is the expiring version: it stays open only until a specific expiry time. In Polycopy, Limit means GTD — the bot default is 4 minutes, and the Settings picker offers 4, 5, 10, 30 and 60 minutes for manual trades. 4 minutes is the shortest Polymarket will accept; anything below it is rejected by the venue. Expiry matters because open orders reserve balance and can fill later if the market returns to your price.

A maker adds liquidity by placing an order that rests on the book and is later matched. A taker removes liquidity by matching against an order already on the book. A Limit/GTD or GTC order can be maker if it rests first, but it becomes taker if your price crosses the spread and fills immediately. FAK and FOK are usually taker-style because they try to execute immediately.

Maker/taker status affects cost, execution certainty, and price quality. Taker orders usually fill faster but may pay higher fees and cross the spread. Maker orders can earn better prices when they rest and fill later, but they may not fill before expiry. Polycopy shows the applicable trading fee before confirmation; Polymarket can also apply taker fees on fee-enabled markets.

Use Limit for most copied trades, when you want a balance between fill rate and price protection. Use Fill and Kill when you want an immediate attempt and no order left open. Use Fill or Kill only when a partial fill is genuinely unacceptable. If a market is thin, the fix is a smaller order — widening slippage in an empty book only authorises a worse fill, it does not find liquidity that is not there.