Ask us anything. We're here to help.

What order types are supported?

Seed CX's order matching engine currently supports the following order types depending on how a participant connects.

  Order Type Can Rest on the Order Book Can Trade Against Resting Orders Time in Force Web API FIX API
Market NO YES Immediate-or-Cancel YES YES
Fill-or-Kill NO YES
Fill-or-Kill NO YES
Post Only Limit YES NO Day YES YES
Market-to-Limit YES YES Day NO YES
Immediate-or-Cancel NO YES


Order Types


Market orders are filled immediately for the specified order quantity at the best possible price available. If the entire order quantity is not available, the order will be partially filled up to what is available in the order book and the remaining quantity will be canceled. If nothing can be filled, the entire order will cancel. 


Limit orders are orders that are filled at a price equal to or better than the specified limit price. Any quantity that isn't immediately filled rests on the order book until it is filled or canceled.

Post-Only Limit

Post-Only Limit orders are limit orders that are constructed to ensure they do not match with any resting order. If the Post-Only Limit order, upon submission, would execute against any resting orders, the Post-Only Limit order is cancelled, ensuring the order always makes liquidity.


Market-to-Limit orders execute against the best available price. In case of partial fills, remaining quantity will become a limit order with a limit price of last fill price.

Time in Force


Day orders are eligible to be executed for the full day trading session. At market close, any remaining quantity on the order book is cancelled.


Fill-or-Kill (FOK) orders must be filled in their entirety, otherwise they are canceled.


Immediate-or-Cancel (IOC) attempt to fill all or some of the order immediately, and cancel any remaining quantity.