Order types

The order type decides when and at what price your order fills. Trade has one ticket for every order. Pick Market, Limit or Stop in the row under Long and Short. It is the same on a phone and on a computer. Stop shows a second switch: Stop market or Stop limit.

Market

A market order fills right away at the best prices in the book. You pay the taker fee.

The price can move while your order fills. This is slippage. Max slippage caps it: the order never fills worse than the current price plus this amount. Pick 0.1%, 0.5% or 1% in Review order before you confirm, or set your default in Settings > Trading > Slippage tolerance. The review shows the Worst price your order can fill at.

If the book can't fill your order within the cap, it does not fill and you see Not filled. Try again or raise the slippage. If only part of it fills, the result shows the size that filled. The rest is cancelled, never left on the book.

Limit

A limit order fills only at your price or better. A buy fills at your price or lower. A sell fills at your price or higher.

If no one matches it, the order waits in the book until it fills or you cancel it. This is GTC (good till cancelled). An order that waits in the book pays the lower maker fee.

The Price field opens with the best price on your side of the book: the best bid for a Long, the best ask for a Short. Tap Best to fill it in again. A line under the size says what your price does, for example "Waits on the book until BTC drops to 63,800." or "Fills at once at 64,300 or lower."

Stop market and stop limit

A stop order waits until the price reaches your Trigger price. Then it sends an order:

• Stop market sends a market order.
• Stop limit sends a limit order at your Limit price. In a fast move it may not fill.

The trigger is checked against the mark price, not the last trade. The ticket shows the current mark next to the trigger field.

A Long (buy) stop must trigger above the current price and a Short (sell) stop below it. Otherwise the ticket says "Buy stop triggers above the current price" (or the reverse). Use stops to enter on a breakout, or to exit a position with reduce-only on. To protect a position, TP/SL is usually simpler.

Post-only

Post-only is for limit orders. It makes sure your order only adds liquidity to the book, so you always pay the maker fee.

If your price would match an order already in the book, the venue cancels your order instead of filling it. You see Post-only would take liquidity. Move your price away from the best bid or ask, or turn post-only off.

Post-only is the Post only, never fill at once checkbox. It shows only when Limit is picked. Without it a limit order is a normal GTC order. On Hyperliquid, post only is also called ALO (add liquidity only).

Reduce-only

A reduce-only order can only make your position smaller. It can never add to a position or flip it to the other side.

In the ticket it is a checkbox that shows only when the side you picked would reduce a position you hold on that venue. To reduce a Long you pick Short, and the box reads Only reduce my Long. To reduce a Short you pick Long, and it reads Only reduce my Short. With it on:

• the order needs no margin;
• Take profit and stop loss is turned off, since there is nothing new to protect;
• the summary shows what the order does to your position, for example "Reduces your Long 0.15 → 0.10331 BTC", and the Realized PnL of the part it closes.

If the position changes before your order reaches the venue (for example a TP closed it), the venue rejects the order. You see Reduce-only rejected: "This order would increase your position." Check your position, then turn Only reduce off or flip the side.

Closing a position from the Close window is always reduce-only. You don't need to set it.

What each venue supports

Lighter: market (a limit at your worst price, from your slippage), limit (good for 28 days) and post-only, stop market and stop limit, reduce-only. Minimum order $10 and a minimum size per market. TP/SL ride with market and limit orders. No trailing stop. Spot pairs on Lighter are view only in Prow.