Central limit order book (CLOB)
A central limit order book (CLOB) is a single, exchange-operated list of all resting limit orders for an instrument, ranked by price and then by time of arrival, against which incoming orders are matched. It is the structure that gives futures one order book and one tape, and it is what a DOM ladder displays.
Senzoukria · Glossary · Updated September 2026
Structure and matching
In a CLOB, every limit order rests at its price on the bid or the ask side. The best bid and best ask form the spread; deeper levels hold the rest of the displayed liquidity. When a market order or a marketable limit order arrives, it is matched against the opposite side starting from the best price, and within a price level in the order the resting orders arrived. That priority rule is why queue position matters for a limit order and why the same displayed size can fill at very different speeds.
- One book per instrument, run by the exchange.
- Priority by price first, then by time within a price.
- Executions are published on one tape with the aggressor side.
Centralised versus decentralised markets
| Market | Order book | Tape | Order flow reading |
|---|---|---|---|
| CME futures | One central book | Exchange-published | Same for every entitled feed |
| Spot forex | Many venues, no central book | No consolidated tape | Describes one venue or broker |
| Crypto | One book per exchange | Per exchange | Valid for that exchange only |
What the DOM shows of the book
The DOM ladder is the visible slice of the CLOB: how many contracts are bid at each price below the market and offered at each price above it. It shows displayed liquidity and its changes. It does not by itself reveal hidden size, iceberg refills or intent, and a level that vanishes may have been pulled or filled; the tape resolves which.
In Senzoukria
The book is shown in the DOM panel, configured through "DOM settings" with "Levels per side" and a "Large orders ≥" threshold; its help text notes that faded levels were seen earlier in the session and are no longer in the live book. The heatmap workspace can also draw the "DOM ladder" on the chart at the exact height of each price. Depth availability, and whether it is price-level or order-by-order, depends on the entitlement of your futures connection. For crypto pairs, the book shown is that exchange's book, for analysis only.
Common mistakes
- Reading a retail forex broker's ladder as market-wide liquidity.
- Treating displayed size as a commitment; resting orders can be cancelled at any time.
- Ignoring queue position when estimating whether a limit order will fill.
Related
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Frequently asked questions
- Why does it matter whether a market has a central limit order book?
- Because order flow analysis depends on a single record of resting orders and executions. With a CLOB, a footprint, a delta series or a heatmap is the same for anyone with an entitled feed. Without one, as in spot forex, every feed describes only its own venue, and two brokers show different footprints for the same pair at the same minute.
- Does the DOM show every order in the book?
- It shows the displayed part of the book at the depth your feed carries. Iceberg orders display only a slice at a time, and some feeds deliver aggregated size per price rather than individual orders. Absence of size at a level means no displayed size in your feed, not proof that nothing rests there.