Order Types
GX Exchange supports a comprehensive set of order types for both perpetual and spot markets.
Market Order
Executes immediately at the best available prices in the order book.
| Parameter | Description |
|---|---|
| Size | Required — the quantity to buy or sell |
| Price | None — fills at best available |
| Time in force | Immediate |
| Partial fills | Yes — fills as much as available, remainder is cancelled |
Market orders always cross the spread. Any unfilled portion is cancelled (they do not rest in the book).
Limit Order (GTC)
A Good-Till-Cancelled limit order rests in the order book until filled, cancelled by the user, or the position is closed.
| Parameter | Description |
|---|---|
| Size | Required |
| Price | Required — maximum buy price or minimum sell price |
| Time in force | Good-Till-Cancelled |
| Partial fills | Yes — partially filled orders remain in the book |
GTC orders provide liquidity to the book and may earn maker fee rebates at high volume tiers.
Immediate-or-Cancel (IOC)
Fills as much as possible immediately, then cancels any remaining quantity.
| Parameter | Description |
|---|---|
| Size | Required |
| Price | Required — acts as a limit price |
| Time in force | Immediate |
| Partial fills | Yes — unfilled remainder is cancelled |
IOC orders are useful for getting the best available fill without leaving a resting order. They never add liquidity to the book.
Fill-or-Kill (FOK)
Fills the entire order immediately or cancels it entirely. No partial fills.
| Parameter | Description |
|---|---|
| Size | Required |
| Price | Required — acts as a limit price |
| Time in force | Immediate |
| Partial fills | No — all-or-nothing |
FOK orders are used when partial execution is unacceptable, such as when hedging a specific exposure.
Post-Only
A limit order that is guaranteed to be a maker (provide liquidity). If it would immediately match against a resting order, it is rejected instead of crossing.
| Parameter | Description |
|---|---|
| Size | Required |
| Price | Required |
| Time in force | Good-Till-Cancelled |
| Partial fills | N/A — never crosses |
Post-Only orders ensure the trader always pays the maker fee (or receives a maker rebate). They are essential for market-making strategies.
Reduce-Only
A modifier that can be applied to any order type. Reduce-only orders can only decrease an existing position, never increase or flip it.
| Behavior | Description |
|---|---|
| No position | Order is rejected |
| Long position, buy order | Rejected (would increase position) |
| Long position, sell order | Accepted (reduces position) |
| Order size > position | Clamped to position size |
Reduce-only is commonly used for take-profit and stop-loss orders to ensure they only close existing exposure.
TWAP (Time-Weighted Average Price)
Splits a large order into smaller suborders executed at regular intervals over a specified duration. See TWAP Orders for the complete specification.
Take-Profit and Stop-Loss
Conditional orders that trigger when the mark price reaches a specified level. See Take-Profit and Stop-Loss.
Order Parameters Summary
| Order Type | Rests in Book | Partial Fills | Maker Fee | Taker Fee |
|---|---|---|---|---|
| Market | No | Yes | No | Yes |
| Limit (GTC) | Yes | Yes | Yes | Yes (if crosses) |
| IOC | No | Yes | No | Yes |
| FOK | No | No | No | Yes |
| Post-Only | Yes | N/A | Yes | Never |
| TWAP | Suborders vary | Yes | Per suborder | Per suborder |
Client Order ID (CLOID)
All order types support an optional client order ID (CLOID) — a user-defined identifier for tracking orders across submission, fill, and cancellation events. CLOIDs can be used for:
- Cancelling orders by CLOID instead of exchange-assigned order ID
- Correlating order events in trading systems
- Deduplicating order submissions