Order Compatibility

TL;DR

Not every combination of type, time-in-force, and execution attribute makes sense. This page is the validity matrix; read it before assembling an order programmatically.

Type × Time in Force

Type	GTC / GTT (rests)	IOC	FOK
limit	Yes, the standard resting order	n/a (use ioc)	n/a (use fok)
ioc	No; IOC never rests	Yes	n/a
fok	No; FOK never rests	n/a	Yes

Time-in-force on Darknyx is carried by the order type plus expiry_slot: a resting order is a limit with an expiry; an immediate order is ioc or fok. See Time in Force.

Type × Execution Attributes

Type	min_fill_size	All-or-none (min_fill_size = amount)
limit	Yes	Yes, rests until a batch can fill it whole
ioc	Yes	Yes, takes whole-or-nothing immediately, residual cancels
fok	Redundant	Implicit; FOK is already whole-or-nothing

Type × Price field

Type	price_limit
limit	Required, the worst acceptable price.
ioc (bid)	Required, the price cap (a "market bid" is an IOC with a cap).
ioc (ask)	Optional; 0 accepts any clearing price (a "market ask").
fok	Required, the whole order must clear at this price or better.

A bid always needs a positive price_limit (a buy at price zero is meaningless, and the collateral must cover the worst case). An ask may set price_limit = 0 to sell into any clearing price.

Modifiability

Action	Supported
Cancel a resting order	Yes, Cancel Order
Modify a resting order (atomic cancel + replace)	Yes, Modify Order
Top up a resting order's anchor pool	Yes, Anchor Top-Up

IOC and FOK orders do not rest, so there is nothing to cancel, modify, or top up after they execute.

Quick validity examples

Intent	Type	Price	min_fill_size	Expiry
Resting bid at a price (GTC)	limit	required	0	far
Resting bid, good for 10 min (GTT)	limit	required	0	deadline slot
Resting bid, fill-whole-or-wait (AON)	limit	required	= amount	far
Cross now up to a cap (market bid)	ioc	cap	0	n/a
Sell now at any price (market ask)	ioc	0	0	n/a
Immediate, whole, or nothing	fok	required	n/a	n/a