What is an Order Book?

5 min read | Last reviewed: 9/23/2025 by GCP

The Heart of the Market

An order book is a real-time list of all the buy and sell orders for a specific asset, like Bitcoin. Think of it as a digital ledger that shows the supply and demand for that asset at every possible price.

It's the core mechanism that allows buyers and sellers to find each other and agree on a price.

Key Parts of an Order Book

Bids (Buy Orders): These are orders from traders who want to buy the asset. They are listed on one side, showing the price they are willing to pay and the quantity they want to buy.
Asks (Sell Orders): These are orders from traders who want to sell the asset. They are on the other side, showing the price they are willing to accept and the quantity they want to sell.
The Spread: The gap between the highest bid price and the lowest ask price is called the spread. A "tight" spread (small gap) usually means the asset is very liquid, with lots of buyers and sellers.

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Test Your Knowledge

What is the primary purpose of an order book?

To track the history of an asset's price.To show a real-time list of all buy and sell orders for an asset.To provide financial advice on when to buy or sell.