Smart Order Options: Post Only and Time in Force
When you place an order in Altrady, the Time in Force setting controls how long the order stays active and how it must be filled. You choose it from a single dropdown in the Trading widget, next to the Place order button.
The dropdown has four options: GTC, Post Only, FOK and IOC. Most are about timing and partial fills, while Post Only is about fees: it keeps your order on the maker side of the book.
This article explains what each option does and when to use it.
Contents
Worked example: GTC, FOK and IOC
Where to find Time in Force
The Time in Force setting sits in the Advanced Trading widget, below the Place order button. It defaults to GTC. Open the dropdown to choose a different option.
Time in Force is available on both standalone orders and Smart Orders.
The four options
Setting | What it does | Partial fills | Unfilled remainder |
|---|---|---|---|
GTC - Good Till Cancelled | Limit order stays active until it is fully filled or you cancel it | Allowed | Rests on the order book |
Post Only - Maker only | Only add the limit order to the book as a maker order; the exchange will reject it if it would fill immediately as a Taker order. Otherwise behaves like GTC | Allowed | Rests on the order book |
FOK - Fill or Kill | Must be filled completely and immediately, at your price or better or it will be cancelled | Not allowed | The whole order is cancelled |
IOC - Immediate or Cancel | Fills as much as possible immediately, at your price or better or it will be cancelled | Allowed | The unfilled part is cancelled |
Good Till Cancelled (GTC)
The order stays on the order book until it is fully filled or you cancel it yourself. This is the default and the most common choice. Use it when you are happy to wait for your price.
Post Only (Maker only)
Post Only makes sure your order is added to the order book as a maker order. A maker order adds liquidity to the book rather than taking it, so it can qualify for a maker fee or rebate instead of the higher taker fee.
When the order is placed, the exchange checks whether it would execute immediately:
- If it would only add to the order book, it is placed as normal, waits in the order book, and when filled, earns the maker fee or rebate. From that point it behaves like a GTC order and rests on the book until filled or cancelled.
- If it would fill immediately (as a taker order), the exchange rejects and cancels it, so you are never charged the taker fee by mistake. No error message occurs; the order is simply cancelled.
Post Only applies to Limit and Stop Limit orders. It has no effect on Market or Stop Market orders, which are always taker orders.
Example: you set a limit buy at 497, expecting it to rest below the market. The market drops quickly, so by the time your order reaches the exchange it would fill immediately as a taker. Because you chose Post Only, the exchange cancels the order instead of filling it.
Fill or Kill (FOK)
The order must be filled completely and straight away, at your limit price or better. If the full amount cannot be filled at once, the whole order is cancelled and nothing is bought or sold. Use it when a partial fill is no use to you.
Immediate or Cancel (IOC)
The order fills as much as it can immediately, at your limit price or better, and cancels whatever is left. Use it when you want to take whatever liquidity is available right now, but do not want a resting order left on the book.
Worked example: GTC, FOK and IOC
Say you place a buy order for 100 coins with a maximum price of USD 500, and the order book has only 60 coins available at USD 500 or better. Here is how each timing option handles it.
Time in Force | Filled immediately | What happens to the rest |
|---|---|---|
GTC | 60 coins | The remaining 40 coins rest on the order book until filled or cancelled |
FOK | 0 coins | The whole order is cancelled, because all 100 cannot be filled at once |
IOC | 60 coins | The remaining 40 coins are cancelled |
(Post Only is left out of this example because it is about fees, not partial fills. A Post Only order that does not fill immediately simply rests on the book, like GTC.)
Troubleshooting and gotchas
- My Post Only order disappeared straight away. That is expected if the order would have filled as a taker. Post Only cancels rather than pays the taker fee. Adjust your price so the order rests in the book.
- Post Only had no effect on my Market order. Post Only only applies to Limit and Stop Limit orders. Market and Stop Market orders are always takers.
- Post Only is not working on my Smart Order. Post Only currently applies to standalone orders only. Use a standalone Limit or Stop Limit order if you need maker-only placement. This order can be contained in a manual posiiton and then converted to a smart position to regain full control.
- Nothing filled with FOK. FOK cancels the entire order unless the full amount can be filled at once. Try IOC if a partial fill is acceptable.
Related articles
Smart Orders: Quick Start Guide
Updated on: 15/06/2026
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