> ## Documentation Index
> Fetch the complete documentation index at: https://docs.polynode.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Orderbook

> Full order book (price/quantity levels, best-first). Use `?depth=` to limit levels per side.

Levels are `[price, quantity]` pairs, best-first on both sides (bids descending, asks ascending).

## Query parameters

| Parameter | Description                          |
| --------- | ------------------------------------ |
| `depth`   | Levels per side (default: full book) |

For streaming updates subscribe to [`perps_book:<instrument>`](/perps/websocket/channels) — every message there is a complete snapshot (including the immediate one on subscribe), so you replace your local book each time rather than merging deltas.


## OpenAPI

````yaml GET /v3/perps/book/{instrument}
openapi: 3.1.0
info:
  title: PolyNode API
  description: >-
    Real-time Polymarket data API with decoded mempool settlements, OHLCV
    candles, and full Polygon JSON-RPC proxy.
  contact:
    name: PolyNode
    url: https://polynode.dev
  license:
    name: ''
  version: 2.0.0
servers:
  - url: https://api.polynode.dev
    description: Production
security:
  - api_key: []
paths:
  /v3/perps/book/{instrument}:
    get:
      tags:
        - Perps
      summary: Orderbook
      description: >-
        Full order book (price/quantity levels, best-first). Use `?depth=` to
        limit levels per side.
      operationId: perps_book
      parameters:
        - name: instrument
          in: path
          required: true
          description: Instrument id (e.g. `6`), symbol (`BTC-USD`), or bare asset (`btc`).
          schema:
            type: string
        - name: depth
          in: query
          required: false
          description: 'Levels per side (default: full book).'
          schema:
            type: integer
      responses:
        '200':
          description: Success
          content:
            application/json:
              example:
                asks:
                  - - '64122'
                    - '1.53392'
                  - - '64123'
                    - '0.47171'
                  - - '64124'
                    - '0.70718'
                bids:
                  - - '64121'
                    - '0.79026'
                  - - '64120'
                    - '0.47131'
                  - - '64119'
                    - '0.70675'
                instrument_id: 6
                symbol: BTC-USD
                timestamp: 1783739410893
components:
  securitySchemes:
    api_key:
      type: apiKey
      in: header
      name: x-api-key

````