Order Book
The order book shows the depth of market for a selected contract — all resting buy and sell orders at each price level.
Reading the order book
The order book is displayed as a two-sided view:
| Bids (Buy Orders) | Asks (Sell Orders) | |
|---|---|---|
| Quantity | Price | Quantity |
| 50 | 85.00 | |
| 30 | 84.50 | |
| 85.50 | 40 | |
| 86.00 | 25 |
- Bids are displayed on the left, sorted highest price first
- Asks are displayed on the right, sorted lowest price first
- The spread is the gap between the best bid and best ask
Key metrics
| Metric | Description |
|---|---|
| Best Bid | Highest price someone is willing to pay |
| Best Ask | Lowest price someone is willing to accept |
| Spread | Best Ask minus Best Bid — a measure of liquidity |
| Depth | Total quantity at each price level |
Using the Depth Ladder
The Depth Ladder provides an alternative visualisation showing price levels as a vertical ladder with quantity bars extending from each level.
- Click a price level on the bid side to pre-fill a sell order
- Click a price level on the ask side to pre-fill a buy order
- Hover over a level to see the aggregate quantity and number of orders
Real-time updates
The order book updates in real time via WebSocket. When you see changes:
- New orders appear as increased quantity at a price level
- Cancelled orders reduce the quantity
- Matched orders reduce both bid and ask quantity simultaneously