OKX spot advanced limit orders are hidden in the order type switch menu on the trading panel. After selecting "Limit Order", three additional modes will appear for you to pick from.
Spot trading supports advanced limit orders with three execution mechanisms: Post Only (Maker only), Fill or Kill (FOK), and Immediate or Cancel (IOC).
Prerequisites
- Logged into your OKX account.
- On the Trade page, confirm the current trading mode is Spot (top left).
- You know you are trading spot, not futures or options.
Entry Point: Limit Order Sub-menu
Advanced limit orders are not a separate order type button; they are an extension of the limit order's "execution condition".
On the spot trading page, the default order type is "Limit Order". Click the dropdown arrow or toggle next to "Limit Order" to expand the list:
- Limit Order (default, good till cancelled)
- Advanced Limit Order
After selecting "Advanced Limit Order", an additional "Execution Condition" option appears below, letting you choose one of: Post Only, FOK, IOC.
Verification: the order type on the trading panel shows "Advanced Limit Order", and you can switch among the three execution conditions.
How to Choose Among the Three Modes
Focus on your scenario, not just definitions:
Mode 1: Post Only (Maker only)
What it is: The order is placed on the order book as a Maker, never taking liquidity immediately. If the price would match immediately (eating someone else's order), the system cancels it right away.
Best for: Those who want to save on fees. Maker fees are usually lower than Taker fees; placing an order and waiting saves costs.
How to use: Set a limit price that won't match instantly. For example, if BTC spot price is $60,000 and you place a buy at $59,500 (well below current price), it won't fill immediately but will sit on the order book. If you place a buy at $60,050, above the lowest ask, the system sees it would immediately eat a sell order and cancels it.
Verification: The order sits in the order book, no immediate fill.
Mode 2: Fill or Kill (FOK)
What it is: The entire order must be filled immediately and completely. If any single unit can't be filled, the whole order is cancelled.
Best for: Traders who must acquire or sell a specific quantity and won't accept partial fills.
How to use: Check the total order book depth at the current price first. If you want to buy 10 BTC but the combined volume of the best ask and next asks is only 8 BTC, a FOK order will be fully cancelled – you get nothing. Use FOK only when the available volume is enough.
Verification: Order either fills completely or gets zero fills and is cancelled.
Mode 3: Immediate or Cancel (IOC)
What it is: The order fills immediately for whatever amount is available; any unfilled remainder is cancelled instantly.
Best for: Those who want to grab some shares quickly and don't want a lingering order on the book.
How to use: If you need 10 BTC but only 6 BTC can be filled at current prices, IOC fills 6 BTC and cancels the remaining 4. You get 6 BTC and can decide what to do next.
Verification: Order partially fills immediately, the rest is cancelled.
Which One to Pick – See the Table
| Scenario | Recommended Mode |
|---|---|
| Want to place an order and save on fees, no rush to fill | Post Only |
| Must buy/sell the full quantity in one go, anything less is useless | FOK |
| Want some amount quickly, give up on the rest | IOC |
| Want to buy but okay waiting for a seller to hit your bid | Post Only |
| Worried about market fluctuation, only want whatever is available now | IOC or FOK |
Risk reminder: If a FOK order is too large and the current depth is insufficient, it will be cancelled immediately with no fill. Don't assume "no fill = not submitted" – the system will show "Order Cancelled". Check order book depth and ensure enough volume is available before re-submitting. With IOC you may get a partial fill; always verify the exact filled amount.
How to Verify Your Order After Placing
After placing the order, go to Assets → Order Center → Open Orders to check:
- Status "Open" or "Placed" → Order is on the book, not yet filled (typical for Post Only).
- Status "Filled" → FOK or IOC fill executed.
- Status "Canceled" → No fill or remaining portion cancelled.
- For FOK if cancelled, it won't appear in Open Orders; check order history instead.
