Order book

The book is the market. It lists every resting order, grouped by price, with the sell side above and the buy side below. Reading it tells you what you can trade right now, at what price, and how much it will cost to move size.

Bids and asks#

• Asks are resting sell orders, sorted with the cheapest at the bottom, closest to the mid. A buyer takes the lowest ask first.
• Bids are resting buy orders, sorted with the highest at the top. A seller takes the highest bid first.
• The two sides never overlap. If they did, the orders would have matched — that crossing is exactly what a trade is.

Mid and spread#

The spread is the gap between the best bid and the best ask. The mid sits halfway between them. The mid is a reference for marking a position; you cannot trade at it unless someone posts there.

A tight spread means cheap immediate execution. A wide spread means immediacy is expensive, and that a limit order is usually the better instrument.

Depth#

Each level shows the size resting at that price, and the running total from the top of the book. The shaded bar behind a row is that level's size relative to the largest level on screen, which makes concentrations of liquidity visible at a glance.

• Size — quantity available at that exact price, in the base asset.
• Total — cumulative quantity from the best price down to that level. This is what a market order of that size would consume.
• Depth bar — the same size, drawn to scale.

Tick grouping#

Prices can be aggregated into coarser buckets: 0.01, 0.05, 0.1, 0.5, 1 USDG. Grouping does not change the market, only the resolution you view it at. A fine grouping shows the exact queue near the touch; a coarse grouping summarises depth further out, which is more useful when sizing a large order.

Your orders on the book#

When one of your limit orders rests at a level, the terminal marks that level so you can see where you are in the market. The order also appears in Open orders with its filled quantity.