Point-in-time order book snapshots.

GET /v1/book

Fetch a full L2 snapshot at a timestamp (or the latest).

Request

GET /v1/book?source=polymarket&market=btc-updown-15m-1792681200&outcome=up&at=2026-10-22T15:10:00Z&depth=6
Authorization: Bearer YOUR_API_KEY

Param	Type	Description
`source`	string	Required
`market`	string	Required · slug, condition id, or token id
`outcome`	string	`up` \| `down` \| `yes` \| `no` when the market is two-sided
`at`	string	ISO-8601 · omit for latest
`depth`	number	Levels per side · default full book

Response

{
  "source": "polymarket",
  "market": "btc-updown-15m-1792681200",
  "token_id": "33339798372916037220…",
  "outcome": "Up",
  "ts_exchange": "2026-10-22T15:10:00.000Z",
  "ts_recv": "2026-10-22T15:10:00.000Z",
  "bids": [{"price": 0.52, "size": 18420}, {"price": 0.51, "size": 22100}],
  "asks": [{"price": 0.53, "size": 15210}, {"price": 0.54, "size": 19840}],
  "spread": 0.01
}

book?at= reconstructs from the nearest 1-minute checkpoint plus deltas.