Technical Definition
Fill-or-Kill (FOK) Order
An order that must be filled completely and immediately, or it is entirely canceled (no partial fills).
By Crypto University Editorial
Immediate-or-Cancel (IOC)
✦ Key Insight
Why It Matters: Ensures all-or-nothing execution; prevents unwanted partial positions in precise strategies. How It Works: Exchange checks if full size can fill instantly at limit/market; if yes, executes; if no, cancels whole order. Common Mistakes: In illiquid pairs (rarely fills); for very l
✕ Common Misconceptions
It is often mistaken for similar sounding terms, but the technical implementation is distinct.
Detailed Explanation
Why It Matters:
Ensures all-or-nothing execution; prevents unwanted partial positions in precise strategies.
How It Works:
Exchange checks if full size can fill instantly at limit/market; if yes, executes; if no, cancels whole order.
Common Mistakes:
In illiquid pairs (rarely fills); for very large sizes.
FAQs
When to use?
For arbitrage or exact sizing needs.
Supported widely?
Yes on most CEX.
In Practice
“Need exactly 5 ETH at $2,500 or less — FOK limit buy; if depth allows full, fills; else, nothing.”