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

# Get best bid/offer

> Returns the top of book (best bid and offer) for a symbol



## OpenAPI

````yaml /institutional/oapi-schemas/orderbook-schema.json get /v1/orderbook/{symbol}/bbo
openapi: 3.0.3
info:
  title: Order Book API
  version: v1.0.0
servers:
  - url: https://api.prod.polymarketexchange.com
    description: Production server
security:
  - bearerAuth: []
tags:
  - name: OrderBookAPI
paths:
  /v1/orderbook/{symbol}/bbo:
    get:
      tags:
        - Order Book
      summary: Get best bid/offer
      description: Returns the top of book (best bid and offer) for a symbol
      operationId: OrderBookAPI_GetBBO
      parameters:
        - name: symbol
          description: Instrument symbol (e.g., "BTC-USD")
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: A successful response.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/v1GetBBOResponse'
components:
  schemas:
    v1GetBBOResponse:
      type: object
      properties:
        symbol:
          type: string
          title: Instrument symbol
        bestBid:
          $ref: '#/components/schemas/v1BookEntry'
        bestOffer:
          $ref: '#/components/schemas/v1BookEntry'
        spread:
          type: string
          format: int64
          title: Spread in price units (best_offer.px - best_bid.px)
        midPrice:
          type: string
          format: int64
          title: Mid price ((best_bid.px + best_offer.px) / 2)
        state:
          $ref: '#/components/schemas/v1InstrumentState'
        transactTime:
          type: string
          format: date-time
          title: Server timestamp of the data
      description: Response containing the best bid and offer.
    v1BookEntry:
      type: object
      properties:
        px:
          type: string
          format: int64
        qty:
          type: string
          format: int64
      description: BookEntry lists a price and volume for a market data record.
      x-deprecated-removed: symbolSubType field was intentionally removed - do not add it back
    v1InstrumentState:
      type: string
      enum:
        - INSTRUMENT_STATE_OPEN
        - INSTRUMENT_STATE_PREOPEN
        - INSTRUMENT_STATE_SUSPENDED
        - INSTRUMENT_STATE_EXPIRED
        - INSTRUMENT_STATE_TERMINATED
        - INSTRUMENT_STATE_HALTED
        - INSTRUMENT_STATE_MATCH_AND_CLOSE_AUCTION
        - INSTRUMENT_STATE_PENDING
      description: InstrumentState represents the state of an instrument.
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT

````

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