How to Use Limit Orders and Post-Only Orders on Hyperliquid

A regular limit order can still take liquidity and pay a taker fee if it happens to cross the spread. A post-only order removes that possibility entirely, it either adds liquidity, or it doesn’t execute at all.

This guide is part of TradeOnDEX’s Hyperliquid how-to series within Perpetual Futures, and pairs with reading the order book.

Disclosure: TradeOnDEX may earn a commission from links to Hyperliquid on this page, at no extra cost to you. Full details at the end of this article.

Limit orders: the basics

A limit order lets you specify the exact price you’re willing to buy or sell at, rather than accepting whatever price a market order fills at. If the market reaches your price, it fills; if it doesn’t, the order simply waits on the book.

This means for you, concretely: a limit order gives you price certainty in exchange for fill uncertainty, the trade-off is the mirror image of a market order’s fill certainty and price uncertainty.

What makes post-only (ALO) different

A standard limit order can still execute immediately if your price happens to cross the current spread, in that case, it behaves like a market order and pays the taker fee. A post-only order (also called ALO, “Add Liquidity Only”) removes that possibility: if your order would fill immediately at placement, it’s cancelled instead, not partially filled and not converted into a market order.

This guarantees one of two outcomes: your order rests on the book as a maker, paying the (typically lower) maker fee, or it doesn’t execute at all.

How to place a limit or post-only order, step by step

1. Open the trading panel for your market and select Limit as the order type.
2. Enter your price and size.
3. To use post-only, check the Post Only box or enable the ALO toggle before submitting.
4. Confirm the order. If post-only would cross the spread and fill immediately, it’s rejected outright. Check your order status rather than assuming it filled or is resting.
5. Using the API directly, set the time-in-force (TIF) parameter to "Alo" on your limit order request to achieve the same behavior programmatically.

Risk: the trade-offs a post-only order doesn’t remove

A rejected post-only order can leave you unintentionally out of a trade you meant to enter. If the market moves before you notice the rejection, you may miss the entry entirely, post-only trades fee certainty for a real chance of non-execution, particularly in fast-moving conditions.

A resting limit order, post-only or not, can be overtaken by the market before it fills. Price can move past your limit level without ever trading there, especially in a fast or gapping move, the same dynamic that applies to Stop Limit orders, covered in the TP/SL guide.

Post-only doesn’t protect you from being on the wrong side of a move, it only affects execution mechanics and fees. A maker-fee limit order that fills right before an adverse price move is just as exposed to that move as any other position; the fee savings have nothing to do with the trade’s directional risk.

Chasing a post-only fill by repeatedly adjusting your price toward the market defeats much of its purpose. If you find yourself repeatedly moving a post-only order closer to the current price to force a fill, you’re approaching the economics of a taker order anyway, just with more manual effort and slower execution.

Limit vs. post-only vs. market: a quick comparison

See it for yourself

Try placing a post-only order slightly inside the current spread on a small size, and watch how it behaves compared to a standard limit order at the same price, the difference becomes clearer in practice than in description. You can review the order panel at app.hyperliquid.xyz.

Frequently asked questions

What happens if my post-only order would fill immediately?

It’s rejected outright, not partially filled, not converted to a market order. You’d need to resubmit at a different price if you still want the trade.

Does a post-only order always pay a lower fee than a market order?

Yes, when it executes, it pays the maker fee (typically lower than the taker fee), because by definition it only fills by adding liquidity to the book.

Is post-only the same as a limit order?

It’s a specific limit order behavior (time-in-force set to ALO), a standard limit order can still take liquidity and pay a taker fee if it crosses the spread at placement, while post-only cannot.

Should I always use post-only for limit orders?

Not necessarily, it’s well suited when fee minimization matters more than guaranteed timing of your entry; if you need more certainty that your order will execute at your intended level, a standard limit order may suit you better.

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TradeOnDEX may earn a commission if you trade through a link on this page, at no extra cost to you. Hyperliquid’s own affiliate/referral terms are still being confirmed for this site, so links here are direct and untracked for now. This article is educational and is not financial advice. See our disclaimer for the full risk warning.