Three Checks Before Canceling a Partly Filled CoW Swap Order

Before canceling a partly filled CoW Swap order, check how much has settled, whether the remaining amount is still live, and whether cancellation has taken effect. A partial fill is not a failed swap: CoW Protocol allows an order to execute in portions across auctions, so the settled trade is complete while the rest may remain available to solvers. That flexibility can help an order find liquidity over time, but it means pressing “cancel” does not necessarily stop a settlement already in progress.

What has already filled, and what remains open?

Start with the order’s executed amount and status, then compare them with the original order details. CoW Protocol’s documentation describes a partially fillable order as one that may execute for less than its total amount; the unfilled portion can remain valid for later auctions. The assets exchanged in a settled portion have already moved according to that trade, while the amount still available to fill is the part cancellation can affect.

That distinction matters when deciding whether cancellation solves the problem. If the order has nearly completed, the remaining amount may be small; CoW Protocol’s limit-order documentation says a small remainder can go unfilled when it is too small relative to the network fees needed to settle it. If the price or amount is no longer suitable, canceling the remainder and placing a new order gives you a fresh set of terms, but a new order may face different market conditions and start waiting for liquidity again. The longer explanation of how partial fills work is in this cowswap article.

Check the order history or CoW Explorer, as the CoW Swap guide recommends for tracking order status. Look for the settled amount and any remaining open amount rather than relying on the wallet balance alone: a balance can show what you hold now, but it does not by itself tell you whether an order is still eligible to settle.

Has the cancellation actually taken effect?

A cancellation request is not the same as a confirmed cancellation. CoW Protocol’s swap and limit-order guides warn that an order may settle while an off-chain cancellation is being processed. So after requesting cancellation, check the order’s status and history again; if a settlement lands first, that portion is final and only any still-open remainder can be stopped.

For a partly filled order, this race affects only the portion that has not already settled. It is possible to request cancellation and then see another fill before the cancellation takes effect. That outcome does not necessarily mean the request failed: the docs describe cancellations as non-immediate, and the order may settle before the request is processed.

• Confirm the order’s status and the amount already executed.
• Check whether a cancellation is requested, pending, or confirmed.
• Review the transaction history for a settlement that occurred during the wait.

If you need to act again, base the decision on the updated remaining amount. Repeated requests without checking status can make it harder to tell whether the order is still active or whether a previous request has already taken effect.

Which cancellation route fits the urgency?

Off-chain cancellation is the lower-cost route; on-chain cancellation costs network gas but records the invalidation in a transaction. CoW Protocol’s documentation says the off-chain route is free and does not require a transaction, while warning that an order can match before the request is processed. On-chain cancellation avoids relying on the API to process the request, but it is not instant either: the order can still match before the transaction is confirmed.

The practical choice is a trade-off between cost and speed of confirmation, not a guarantee of stopping the order before its next possible settlement. For most readers who can tolerate the processing window, off-chain cancellation avoids paying gas for the cancellation itself. If stopping further execution is urgent, the on-chain route may provide more direct confirmation once mined, but it carries a gas cost and the same pre-confirmation race. The CoW Protocol guide advises using a high priority fee and signing swiftly for this route.

Before confirming either option, verify the order and network shown in the interface, then review the result in order history. If the order is still open afterward, check whether the request is pending or whether the interface still offers cancellation. CoW Protocol’s guides describe cancellation through the activity panel or open-order menu and say a confirmed canceled order moves out of open orders into order history.

The key decision is whether the remaining portion still fits your price and timing needs. Leave it open if those terms remain acceptable and you are willing to wait for more liquidity; cancel it if you no longer want further execution, while accounting for the settlement race. Watch three signals next: the remaining order amount, any new settlement in the history, and the final cancellation status.