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Historical Data Availability — Coverage is market-specific.
  • Orderbook data exists for a subset of markets from 2025-09-01 on Polymarket and 2026-02-17 for Kalshi, but coverage is not continuous.
  • Continuous Polymarket crypto-related market coverage begins on 2026-02-04. Continuous Kalshi crypto-related market coverage begins on 2026-02-25.
  • Continuous coverage for all markets begins 2026-04-02 for Polymarket and 2026-03-31 for Kalshi.
Use the date-range endpoints to verify a specific condition ID or ticker.

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Overview

The Entity Market Data API gives you programmatic access to Polymarket and Kalshi order book data, including live snapshots and historical tick-level events. For most integrations, use the official SDK or CLI first. Raw HTTP is still supported for custom workflows. Use it to:
  • Retrieve full order book snapshots (bids and asks)
  • Track price changes over time
  • Build trading strategies and analytics dashboards

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Quick start (SDK/CLI preferred)

Create an API key

Sign up and generate your first API key in under a minute.

Python SDK

Use the official SDK for both Polymarket and Kalshi endpoints.

CLI

Use the standalone CLI for Polymarket and Kalshi endpoints.

API reference

Full endpoint documentation with request/response examples.

Helper scripts

Python scripts for finding condition IDs and working with market data.

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Make your first request

from poly_storage_sdk import PolyStorageClient

client = PolyStorageClient(api_key="YOUR_API_KEY")

data = client.polymarket.get_market_data(
    condition_id="0x8213d395e079614d6c4d7f4cbb9be9337ab51648a21cc2a334ae8f1966d164b4",
    date="2026-02-13",
    limit=5,
)

print(data["data_count"])

See the full getting started guide

Step-by-step instructions with multi-language code examples.