Order Types

Understanding different order types and how they execute in the market.

Every order carries a price bound: each type below has an explicit worst-case price that is signed and margined exactly. There are no unpriced order types (market) — for immediate execution, use a crossing Limit IOC with your slippage tolerance as the limit price.

Order Type Execution Behavior

• Limit — Executes at your specified price or better.

  • To trade immediately (market-style execution), place a crossing Limit IOC: set the limit price at your maximum acceptable slippage (e.g. buy with limit = mark × 1.01 for a 1% bound). It fills immediately up to your bound and cancels any remainder — speed of a market order, with a guaranteed worst-case price.

  • Supports an optional reduceOnly flag (see below).

• Stop-Limit — Becomes a limit order when the market reaches your stop (trigger) price. Requires both stopPrice and limitPrice.

• Stop-Loss — Closes (part of) your position when the market moves against you. Places as a Stop-Limit: requires a stopPrice (trigger) and a limitPrice (worst acceptable execution price).

• Take-Profit — Closes (part of) your position at a profit target: becomes a limit order when the market touches your trigger price. Requires a stopPrice (trigger) and a limitPrice (worst acceptable execution price).

Reduce-Only Orders

reduceOnly: true marks an order that may only ever reduce your position — it can never open one, flip it, or grow it. Supported on Limit, Stop-Limit, Stop-Loss and Take-Profit, resting or immediate.

Requirements:

• You must hold an open position in that instrument.

• The order must be on the opposite side to the position.

• Quantity must not exceed the position size.

• Where several reduce-only orders would be reached by the same price move, their combined quantity must not exceed the position either. A stop-loss below the market and a take-profit above it are not combined — no single move reaches both — so you may hold both at full size.

A reduce-only order may rest on the book. It is kept in line with your position as that position changes, and cancelled once the position is closed or flipped.

Post-Only Orders

instructions: ["PostOnly"] marks an order that only adds liquidity. If it would match immediately, it is cancelled. Supported on Limit and Stop-Limit with GTC, GTD or DAY.

Stop-Loss & Take-Profit Modes:

SL/TP orders support two modes controlled by the closePosition parameter:

Managed Orders (closePosition: true):

• Quantity automatically syncs with position size as it changes

• Only one managed SL and one managed TP allowed per instrument

• One-Cancels-Other (OCO): when managed SL or TP fills, the other is automatically cancelled

• Automatically cancelled if position closes or direction flips

• Cannot specify quantity - server manages it based on current position

• Requires either an open position, or a resting entry order on the same instrument to attach to. It can only reduce a position — it can never open one.

Unmanaged Orders (closePosition: false):

• Fixed quantity specified by you (like regular orders)

• Multiple unmanaged SL/TP orders allowed per instrument

• Requires an open position. Place the position first, then attach the trigger.

• Reduce-only: it can only close part or all of your position — it can never open or flip one.

• The quantity you set is an upper bound: the order is kept in line with your position as it changes, and cancelled once the position closes or flips.

Attaching SL/TP to an entry order

There is no native bracket / OTOCO order type, and no OCO between an entry order and its SL/TP — OCO exists only between a managed SL and a managed TP. What you can do:

• Managed SL/TP may be placed while an entry order is still resting. They stay inert until the entry fills, then size themselves to the resulting position.

• Unmanaged SL/TP require the position to exist first, so place them after the entry fills.

Neither can open a position on its own, so an entry that never fills cannot leave you with a trigger that opens one. If you cancel the entry order, cancel any managed SL/TP you attached to it.

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Time in Force

Controls how long an order remains active:

• GTC (Good-Til-Canceled) - Remains active until filled or manually canceled

• IOC (Immediate-or-Cancel) - Fill immediately, cancel any unfilled portion

• FOK (Fill-or-Kill) - Fill entire order immediately or cancel entirely

• GTD (Good-Til-Date) - Expires at specified expiryDate timestamp

• DAY - Expires at end of trading day 00:00:00 UTC

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Order Type Compatibility Matrix

Type	GTC	GTD	FOK	IOC	DAY
Limit	✔️	✔️	✔️	✔️	✔️
StopLimit	✔️	✔️	✔️	✔️	✔️
StopLoss	❌	❌	✔️	✔️	❌
TakeProfit	❌	❌	✔️	✔️	❌

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Required Price Fields

Type	limitPrice	stopPrice
Limit	required	—
StopLimit	required	required
StopLoss	required	required
TakeProfit	required	required