Why Are OKX Post-Only Orders Automatically Canceled?
A Post Only order is canceled automatically because the price you set would immediately eat into existing orders on the order book. The system determines that the order would act as a Taker rather than a Maker, so it cancels it outright without entering the order book.
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This is normal Post Only behavior, not a system bug. Below we explain how to check whether your order triggered the cancellation condition and how to adjust it.
Prerequisites
You have selected the "Advanced Limit" order type on the OKX trading interface.
The execution mechanism is set to "Post Only".
You know whether you are placing a buy or sell order and at what price.
Step 1: Check the current best bid/ask on the order book
Open the order book on the OKX trading page and locate the current highest bid price (Bid) and lowest ask price (Ask):
Buy order: if your price ≥ current lowest ask, it will be canceled.
Sell order: if your price ≤ current highest bid, it will be canceled.
Completion standard: See the real-time prices on the order book and clearly understand the relationship between your order price and the current market price.
Step 2: Adjust the price according to your situation
Case A: Buy order was canceled
Your buy price is too high – it is higher than or equal to the current lowest ask.
Solution: Lower your buy price to below the current lowest ask. For example, if the current lowest ask is 30,740 USDT, placing a buy order at 30,000 USDT will enter the order book and wait for execution.
Completion standard: The set price is lower than the current lowest ask; after submitting, the order status shows as "Open" or "Pending".
Case B: Sell order was canceled
Your sell price is too low – it is lower than or equal to the current highest bid.
Solution: Raise your sell price to above the current highest bid.
Completion standard: The set price is higher than the current highest bid; after submitting, the order status shows as "Open" or "Pending".
Step 3: Submit the adjusted order again
On the trading page, re-enter the adjusted price while keeping the settings "Advanced Limit" and "Post Only" unchanged, then click submit.
Completion standard: The page shows that the order has been submitted with a status of "Open" or "Pending" and has not been automatically canceled.
Common reasons for failure
The order book price moved at the moment of submission
In the split second between entering your price and clicking "Submit", the order book may have shifted, causing your price to exactly hit the cancellation threshold. It is recommended to set your price a bit further away from the current market, leaving a buffer of several dozen minimum price units (ticks).
Risk notice
The core purpose of Post Only is to save on fees: Maker fees are usually lower than Taker fees. However, if you insist on posting solely to save fees and miss your entry timing, you need to weigh the cost-effectiveness yourself.
Not every order needs Post Only: If your goal is to "get filled quickly", use a market order or a regular limit order (default GTC) directly; there is no need to select Post Only.
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How to confirm the operation is complete
After submitting the order, check its status under [Order Management] → [Open Orders]. If it shows "Open" or "Pending", it means the order has entered the order book and was not canceled. Afterwards, wait for the market price to touch your order price and the order will be filled automatically.
If it is still canceled, repeat Step 2 and check whether the new price still falls within the "immediate execution" range.
