An order book is a changing list of unexecuted intentions; read price, quantity, side, quote currency, and distance from market together.
Read price levels and sides
A central limit order book organizes resting orders by price. Bids offer to buy the base asset; asks offer to sell it. The highest bid and lowest ask are the best resting prices. Their difference is the spread and their average is the midpoint. A trade occurs when an incoming order accepts a resting price.
For SUI/USDC, a bid at 1.18 means a buyer offers 1.18 USDC for each SUI. An ask at 1.20 means a seller requests 1.20 USDC for each SUI. The 0.02 USDC spread can also be expressed relative to the midpoint, making comparisons across differently priced assets easier. The midpoint is a reference, not necessarily an executable price.
Calculate notional in the quote asset
DeepBook indexer order-book entries are consumed by this application as price and quantity pairs. The server multiplies each level's price by its base quantity and sums bids and asks separately. The result is resting quote notional. It must not be called executed buy or sell volume, and bids and asks must not be described as long and short positions.
SUI/USDC and DEEP/USDC notionals are in USDC. DEEP/SUI notionals are in SUI, not USD. Comparing them requires a separately sourced, timestamped SUI price and disclosure of the conversion.
- Best bid: highest resting buy price.
- Best ask: lowest resting sell price.
- Spread: best ask minus best bid; midpoint: their average.
Interpret imbalance cautiously
A ratio above one means more displayed bid than ask notional in the selected levels. It may indicate visible support, but does not prove buyers will execute. Orders may be distant, canceled, or replaced, while aggressive flow can arrive without first resting in the book.
The site's SUI/USDC stats sum the returned visible levels, while pool cards use a broad inclusion filter from one-fifth to five times a reference midpoint when available. Any ratio must therefore be interpreted with its collection and price-band method. The UI's pressure presentation and server alerts are separate views; avoid assuming exact undocumented alert equivalence.
Connect the book to execution risk
Estimate a marketable order by walking the opposite side until reaching the target quantity. The weighted average indicates snapshot slippage. A limit order specifies a worst acceptable price but may not fill, and queue position can matter. No snapshot guarantees execution: latency, matching priority, fees, cancellations, and competing traders can change the result.
Illustrative spread and imbalance
Consider a simplified SUI/USDC book containing only two aggregate sides. These invented values show the arithmetic, not a live DeepBook market.
- Best bid
- 1.19 USDC for 4,000 SUI = 4,760 USDC
- Best ask
- 1.21 USDC for 3,000 SUI = 3,630 USDC
- Midpoint / spread
- 1.20 USDC / 0.02 USDC (about 1.67%)
- Displayed ratio
- 4,760 / 3,630 = 1.31 bid-to-ask
The selected snapshot is bid-heavy, but the ratio does not predict the next trade. The bid could be canceled or an aggressive seller could consume it.
Common interpretation traps
- Labeling resting bids as longs, asks as shorts, or either side as executed flow.
- Ignoring how far a large order is from the midpoint when summing depth.
- Mixing SUI-denominated DEEP/SUI notional with USDC values without conversion.
Frequently asked questions
Is the midpoint the current market price?+
It is a useful reference between the best quotes, but it may not be executable. Last trade, index price, and midpoint are distinct values.
Why can a large order disappear?+
A resting limit order can generally be canceled or modified before execution. Book updates therefore represent conditional intentions, not committed future trades.
Does a bid-heavy book mean I should buy?+
No. Imbalance is one venue-specific snapshot. Price distance, persistence, executions, other venues, and your risk plan all matter.