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

# Get Orderbooks

> Fetch current orderbooks for multiple markets. Accepts both Polymarket token IDs and Kalshi market IDs. The endpoint automatically detects the venue based on the ID format. Returns an array of orderbooks with venue information.



## OpenAPI

````yaml /openapi.json post /api/v1/markets/orderbooks
openapi: 3.1.0
info:
  title: Synthesis API
  version: 1.0.0
  description: Unified prediction market API for Polymarket and Kalshi.
servers:
  - url: https://synthesis.trade
security: []
tags:
  - name: Projects
    description: Create and manage project accounts, sessions, and account API keys.
  - name: Accounts
    description: >-
      Authenticate and manage account-level sessions, account API keys, and
      public account preferences.
  - name: Markets
    description: Unified market discovery and analytics across Polymarket and Kalshi.
  - name: Polymarket
    description: Polymarket market data, prices, orderbooks, trades, and holders endpoints.
  - name: Kalshi
    description: Kalshi market data, events, history, leaderboard, and profile endpoints.
  - name: Wallets
    description: Wallet management routes. Each wallet supports multiple chains.
  - name: Polygon
    description: >-
      Polygon wallet routes for balances, orders, minting, redemption,
      withdrawals, and swaps.
  - name: Polygon Copytrades
    description: Polymarket copytrade configuration and management for Polygon wallets.
  - name: Solana
    description: >-
      Solana wallet routes used for Kalshi balances, KYC, orders, redemption,
      and withdrawals.
  - name: News
    description: News endpoints with market and event matching.
  - name: WebSockets
    description: >-
      Real-time streaming endpoints for orderbooks, trades, balances, and live
      data feeds.
paths:
  /api/v1/markets/orderbooks:
    post:
      tags:
        - Markets
      summary: Get Orderbooks
      description: >-
        Fetch current orderbooks for multiple markets. Accepts both Polymarket
        token IDs and Kalshi market IDs. The endpoint automatically detects the
        venue based on the ID format. Returns an array of orderbooks with venue
        information.
      operationId: get-market-orderbooks
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: array
              items:
                type: string
              description: >-
                Array of market identifiers. Accepts both Polymarket token IDs
                and Kalshi market IDs. Maximum 1000 markets per request.
              example:
                - >-
                  21742633143463906290569050155826241533067272736897614950488156847949938836455
                - KXBTC-25-T100000
      responses:
        '200':
          description: Orderbooks array
          content:
            application/json:
              example:
                success: true
                response:
                  - venue: polymarket
                    orderbook:
                      condition_id: >-
                        0xbd71b43bb47eb60dbcb41fa25df2a0ed4da612873d6e0447a2c730bd4cc25910
                      token_id: >-
                        21742633143463906290569050155826241533067272736897614950488156847949938836455
                      bids:
                        '0.61': '1000'
                        '0.60': '800'
                      asks:
                        '0.62': '900'
                        '0.63': '600'
                      best_bid: '0.61'
                      best_ask: '0.62'
                      hash: abc123
                      created_at: '2026-01-01T00:00:00'
                  - venue: kalshi
                    orderbook:
                      market_id: KXBTC-25-T100000
                      'yes':
                        bids:
                          '58': '25'
                        asks:
                          '60': '15'
                        best_bid: '58'
                        best_ask: '60'
                      'no':
                        bids:
                          '40': '15'
                        asks:
                          '42': '20'
                        best_bid: '40'
                        best_ask: '42'
                      sequence: 12345
                      created_at: '2026-01-01T00:00:00'
        '400':
          description: Invalid request
          content:
            application/json:
              example:
                success: false
                response: Invalid markets
      security: []

````