> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kairos.trade/llms.txt
> Use this file to discover all available pages before exploring further.
# Time-in-Force
> GTC, IOC, FOK, and GTD — controlling how long your order lives
A limit order needs one more instruction: how long should it wait, and what should happen if only part of it can fill? That instruction is time-in-force. This chapter walks through the four you'll use, with an example of each.
## What Is Time-in-Force?
Time-in-force tells the exchange **how long your order should stay active** and **what to do if it can't fill completely**.
Think of it as instructions on a delivery package:
* "Deliver anytime" (GTC)
* "Deliver now or return it" (IOC / FAK)
* "Deliver the whole thing now or don't bother" (FOK)
* "Deliver before Friday or return it" (GTD)
## GTC — Good Till Cancelled
**"Keep my order open until I cancel it."**
Your order rests on the book for as long as it takes. It stays there until it gets filled or you manually cancel it. This is the most common time-in-force for limit orders.
> **You:** Buy 100 shares at **\$0.50**, GTC
>
> **Exchange:** Got it. I'll keep this open.
>
> *...3 hours later, someone sells at **\$0.50**...*
>
> **Exchange:** Filled! 100 shares at **\$0.50**
**Use when:** You're patient and want to wait for your price.
## IOC / FAK — Immediate or Cancel (Fill and Kill)
**"Fill whatever you can right now. Cancel the rest."**
IOC and FAK mean the same thing — different exchanges just use different names. The exchange tries to fill as much of your order as possible instantly. Anything left over gets cancelled — it does not rest on the book.
> **You:** Buy 100 shares at **\$0.55**, IOC
>
> **Book:** 60 shares available at **\$0.55**
>
> **Result:** 60 filled, 40 cancelled
**Use when:** You want to grab what's available without leaving an order sitting around.
## FOK — Fill or Kill
**"Fill the entire order right now, or cancel the whole thing."**
It's all or nothing. If the exchange can't fill your complete order instantly, nothing happens.
> **You:** Buy 100 at **\$0.55**, FOK — only 60 available
>
> **Result:** Entire order cancelled. No fill at all.
> **You:** Buy 100 at **\$0.55**, FOK — 150 available
>
> **Result:** 100 shares filled at **\$0.55**
**Use when:** You need the full amount or nothing — partial fills would mess up your strategy.
## GTD — Good Till Date
**"Keep my order open until a specific date/time."**
Like GTC, but with an expiration. Your order rests on the book and automatically cancels if it hasn't filled by the deadline you set.
> **You:** Buy 100 shares at **\$0.45**, GTD March 15
>
> *...March 15 arrives, no fill...*
>
> **Exchange:** Time's up. Order cancelled.
**Use when:** You want to wait for your price, but only up to a certain point — like before a market resolves or an event happens.
**On Kairos:** GTD takes a duration, not a date. Send
`expiration_minutes` alongside `time_in_force: "GTD"` — minutes from now,
between 1 and 43,200 (30 days). It is required for GTD.
## Side-by-Side Comparison
| Type | Rests on book? | Partial fill? | Cancels when? |
| - | - | - | - |
| **GTC** | Yes | Yes (fills over time) | When you cancel it |
| **IOC / FAK** | No | Yes (takes what it can) | Immediately after attempt |
| **FOK** | No | No (all or nothing) | Immediately if can't fill all |
| **GTD** | Yes | Yes (fills over time) | At the expiration date/time |
**On Kairos:** these are the only accepted `time_in_force` values —
`GTC`, `FOK`, `FAK`, `IOC`, `GTD` — and `GTC` is the default. Every venue
accepts all five except Opinion, which is `GTC` only. An unrecognised value is
rejected, not downgraded. See [Order Types](/guides/order-types#time-in-force).
## How to Choose
**Next:** [Execution & Slippage](/learn/execution-and-slippage) — what actually happens to your order once it reaches the book.
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