Polymarket limit orders: price, expiry and fills

An illustrative buy limit of 0.58 accepts prices no higher than that boundary. An available ask at 0.61 does not meet it. Recording the limit cannot require another participant to supply shares more cheaply than their offer.

If a practice book offers 10 shares at 0.56, that price is better than the 0.58 boundary. Keep the actual price rather than substituting the limit in a ledger: accounting depends on fills as well as submitted parameters.

GTC keeps an order active until filling or cancellation; GTD gives it an expiry. Separate the order lifetime from the event deadline when reading these modes. Order expiry does not resolve the market or change a position already obtained.

Record creation time and stated expiry in one time zone. When an interface uses local dates, compare complete dates and times rather than day names alone. Exact technical expiry requirements should be checked separately against the current product and interface.

Post-only is designed to rest in the book. If an order would cross opposing interest immediately, it is rejected rather than immediately executed. This is a distinct behavior setting, not another name for every limit order submitted to a market.

An illustrative buy at 0.58 against ask 0.56 can meet interest immediately without that setting. Post-only requires a different validation result. When reading a rejection, inspect the mode and book rather than concluding that the event itself has finished.

Of an illustrative 80 shares, 30 can fill while 50 remain in the book. Each portion has its own state. An open order does not prove that no fills have occurred, so inspect both the trade record and remaining order quantity.

Cancellation affects the remainder; it cannot erase an executed portion by withdrawing the original intention. Pending matching delays can impose specific cancellation restrictions. Read the platform response and balance before updating your own quantity calculation or describing the operation as complete.