Core order families
User-facing modifiers
Reduce only
Reduce-only orders can only decrease existing exposure.Post only
Post-only orders are used to add liquidity only. They do not execute immediately as takers.Take profit / stop loss
These are trigger orders evaluated against mark price. See Take Profit And Stop Loss.Expiration
Order packets can carry alast_valid_slot, which acts like an expiry.
Match limit
Advanced callers can setmatch_limit to cap how many resting FIFO orders or spline price levels an incoming order may consume.
This is separate from the open-order cap. match_limit controls taker-side matching work for one incoming order. The open-order cap controls how many resting limit orders a trader may already have on one market side.
For FIFO matching, each maker order consumes one match_limit unit. For spline matching, one spline price level consumes one match_limit unit even if multiple splines participate at that level.
Cancel existing
Some order flows can request cancellation of conflicting resting orders instead of failing a margin check immediately.How to think about order choice
Use market / IOC when
- speed matters most
- you are willing to take available liquidity
Use limit when
- you need a price bound
- you are okay with resting if not fully filled
Use post-only when
- you explicitly want maker behavior
- you do not want an aggressive fill
Self-trade behavior
Phoenix also lets the matching engine choose how to handle self-crosses. At the protocol layer, the supported behaviors are:AbortCancelProvideDecrementTake
CancelProvide unless a caller overrides it.