Order Book

Return the current order book for a symbol: a list of bids (buy orders) and asks (sell orders), each as a [price, quantity] pair, sorted best-first.

curl "https://api.spacedex.com/api/v1/depth?symbol=BTCUSDT&limit=5"

{
  "lastUpdateId": 84461209,
  "bids": [
    ["64210.50", "0.812"],
    ["64210.00", "1.204"]
  ],
  "asks": [
    ["64211.00", "0.640"],
    ["64211.50", "2.155"]
  ]
}

The first bid and first ask are the best prices; the gap between them is the spread. For a live book that stays in sync without repeated snapshots, subscribe to the depth stream (see Market Streams) and apply updates against lastUpdateId.