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ARBITER

Query normalized Polymarket and Kalshi markets, historical books, wallet analytics and matched events through one data API.

3.5/ 5Editorial rating0 user reviews
Visit official sitearbiterapi.com
Available on
REST API, WebSocket, TypeScript
Pricing
Pricing not confirmed

Screenshots and interface

Product preview1 / 2

Unified data API entry page and sample market view.

What is ARBITER?

ARBITER combines discovery, historical data and live updates under one API key. Its common price scale and timestamps reduce the work of joining two venue feeds, while historical books, candles and wallet endpoints support research beyond a current-price widget.

Who it is for

  • Developers integrating Polymarket and Kalshi
  • Researchers comparing matched contracts across venues
  • Teams building wallet analytics or historical charts

Features and coverage

Available on
REST API, WebSocket, TypeScript
Markets & venues
Polymarket, Kalshi
  • Unified discovery

    Search markets and events across both venues.

  • Normalized fields

    Prices use a 0–1 probability scale and timestamps use Unix milliseconds.

  • Historical data

    Query trades, order-book snapshots and OHLCV candles from one-minute to daily intervals.

  • Point-in-time queries

    Use supported at_time reads for historical prices.

  • Wallet analytics

    Read positions, activity, trades and P&L through dedicated endpoints.

  • Cross-platform matches

    Find potentially corresponding events before comparing their prices.

  • Live updates

    Stream supported trades, prices and book changes over WebSocket.

Workflows with ARBITER

Compare a matched event

Discover its cross-platform match, inspect both contract definitions and compare prices on the same scale. Add depth and venue fees before calculating an executable spread.

Build a historical view

Retrieve the market, choose an interval and page through the required trade or candle range. Use book snapshots when the task depends on liquidity.

Research a wallet

Read its positions and activity, then link each entry back to the underlying market.

Pricing and total cost

An account and API key are required. A numerical subscription price is not published on the product and introduction pages; check the account plan before a large ingestion job.

Getting started

Before you start: The introduction labels the Python SDK as coming soon even though Python examples appear elsewhere; direct HTTP provides a clear integration path.

  1. Create an account and API key.
  2. Send X-API-Key with a small markets request.
  3. Preserve venue identifiers alongside normalized IDs.
  4. Choose REST history or WebSocket updates for the task.
  5. Use the TypeScript SDK or direct HTTP against the documented endpoints.

Open documentation

Useful links

What to check

  • The introduction labels the Python SDK as coming soon even though Python examples appear elsewhere; direct HTTP provides a clear integration path.
  • A cross-platform match still needs compatible settlement rules and deadlines.
  • Historical coverage must be checked for the specific market and interval.

A closer look

Ratings & reviews

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Editorial rating
3.5/ 5
0 user reviews
Polytoolhub editorial

Our take on ARBITER

Normalized markets, point-in-time queries and wallet data provide useful building blocks. Public pricing and the Python SDK's release status need clarification before choosing it for production.

Based on documented features, setup and access terms. How we rate

User reviews 0

The main score switches to user ratings after 5 published reviews.

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Frequently asked questions about ARBITER

Which venues does it cover?

The documented integration covers Polymarket and Kalshi.

How are prices represented?

As probabilities between zero and one.

Can it return more than candles?

Yes. The reference includes trades and historical order-book snapshots.

Does an API match establish identical contracts?

Inspect the original rules and resolution conditions before comparing an executable trade.