Order Book
Place orders, watch them match, and see how price discovery works.
How Order Books Work
An order book is the core data structure of any exchange. It collects limit orders — intentions to buy or sell at a specific price — and stacks them by price level. Buy orders (bids) sit below, sell orders (asks) sit above, and the gap between the best bid and best ask is the spread.
When a new order arrives that can match against a resting order on the other side, a trade happens at the resting order's price. This is price-time priority: the best price gets matched first, and at the same price, whoever was first in line wins.
Market orders skip the line — they execute immediately against whatever's available, consuming liquidity from the book. The depth chart shows how much cumulative quantity sits at each price level, giving you a sense of where the support and resistance are.
Related: Behavioral Finance