Polymarket CLOB Market Data API

openapi: 3.1.0
info:
  title: Polymarket APIs (CLOB and Gamma) CLOB Market Data API
  version: '1.0'
  description: "Polymarket exposes several HTTP APIs documented at\nhttps://docs.polymarket.com/:\n\n  * CLOB API (`https://clob.polymarket.com`) for order book,\n    trading, and pricing operations.\n  * Gamma API (`https://gamma-api.polymarket.com`) for read-only\n    market, event, and metadata access.\n\nThis specification captures a representative subset of endpoints\nfrom both surfaces. CLOB trading endpoints require the\nPOLY_API_KEY / POLY_ADDRESS / POLY_SIGNATURE / POLY_PASSPHRASE /\nPOLY_TIMESTAMP header set; Gamma endpoints are fully public.\n"
  contact:
    name: Polymarket Documentation
    url: https://docs.polymarket.com/
servers:
- url: https://clob.polymarket.com
  description: Polymarket CLOB API
- url: https://clob-staging.polymarket.com
  description: Polymarket CLOB staging
- url: https://gamma-api.polymarket.com
  description: Polymarket Gamma API
tags:
- name: CLOB Market Data
  description: Public CLOB market data.
paths:
  /midpoint:
    get:
      tags:
      - CLOB Market Data
      operationId: getMidpointPrice
      summary: Get midpoint price for a market
      description: Returns the average of the best bid and best ask prices for the given token.
      servers:
      - url: https://clob.polymarket.com
      parameters:
      - in: query
        name: token_id
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Midpoint
          content:
            application/json:
              schema:
                type: object
                properties:
                  mid:
                    type: string
                    description: Midpoint price as a decimal string.
  /time:
    get:
      tags:
      - CLOB Market Data
      operationId: getServerTime
      summary: Get server time
      description: Returns the current Unix timestamp of the CLOB server.
      servers:
      - url: https://clob.polymarket.com
      responses:
        '200':
          description: Server time
          content:
            application/json:
              schema:
                type: object
                properties:
                  time:
                    type: integer
                    format: int64
components:
  securitySchemes:
    polyApiSignature:
      type: apiKey
      in: header
      name: POLY_API_KEY
      description: 'Polymarket CLOB authenticated trading endpoints require five

        headers: POLY_API_KEY, POLY_ADDRESS, POLY_SIGNATURE,

        POLY_PASSPHRASE, POLY_TIMESTAMP. Only POLY_API_KEY is modelled

        here because OpenAPI security schemes describe a single header

        each; in practice, all five must be sent on each request.

        '