TradingIntermediate#Execution#Fees
Post-Only Order
P
Definition
A venue-specific limit-order instruction intended to prevent immediate matching so the order rests on the book if accepted. Exact cancellation, rejection, adjustment, and fee behavior depend on the venue.
Source reviewed
- Hyperliquid Docs: Order types opens in a new tab
Supports: Hyperliquid defines Post Only (ALO) as an order added to the book rather than executing immediately and documents venue-specific order handling.
- Hyperliquid Docs: Exchange endpoint opens in a new tab
Supports: Hyperliquid documents that ALO limit orders are canceled instead of immediately matching, while other time-in-force choices have different behavior.
Concept Diagram
Key Takeaways
1
Post-only semantics are venue-specific and can cancel, reject, or otherwise handle an immediate match
2
If accepted, it rests first but can remain unfilled, fill partially, be canceled, or lose priority
3
Maker fee schedules and rebates are not universal and must be checked per product and account
4
Post-only does not guarantee execution, price improvement, profit, or protection from market risk
Practical Example
A user checks that the selected venue cancels a post-only order that would immediately match, verifies the product's maker fee schedule, and submits a valid limit order. They monitor its accepted, canceled, partial-fill, and queue state rather than assuming the instruction produces a rebate or an execution.
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Related Terms
Blockchain
Hyperliquid L1A layer-1 blockchain whose documentation describes HyperCore spot and perpetual order books and HyperBFT consensus. Product availability, latency, fees, liquidity, and risk remain deployment- and market-specific.
Trading
Tick SizeThe smallest permitted price increment for an order on a specific trading venue and market. It is a venue rule, not a universal property of the asset or a measure of execution quality.
Strategy
TWAP (Time Weighted Average Price)An execution method that schedules parts of an order across a defined time interval. Its schedule, sizing, slippage controls, fill behaviour, and result are venue- and configuration-specific.
Trading
SlippageThe difference between a quoted or expected trade result and the result that can execute under the protocol's state and limits.
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