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You’re here to find edges in prediction-market data. This guide gets you from API key to a runnable backtest, then points you at the deeper material.
The most-requested quant dataset: orderbook tick history. Every placement, update, cancel, and fill as bulk Parquet — the raw stream behind queue-position modeling, fill-probability estimation, and full book replay. Quote any slice for free; $50 in credits on signup.
You’ll be ready to:
  • Pull historical orderbook + trade + candle data for any market
  • Reconstruct any wallet’s full position history and P&L
  • Build smart-money signals from the leaderboard endpoint
  • Stream live signals (trades, pending trades, orderbook) over WebSocket

10 minutes to a backtest

Goal: pull 30 days of orderbook snapshots for the highest-volume open market, plus the trade tape, plus the candle series — enough to run a real backtest.
That’s three free endpoints, no rate-limit risk, ~30 lines of code, ready for pandas/numpy/whatever your strategy framework is.
Every endpoint used here is free and unlimited. Run as many backtests as you want.

The data tools quants reach for first

Orderbook history

Per-token L2 snapshots from Jan 1 2026. Simulate fills against the real book — see Orderbook Replay for the pattern.

Candlesticks

OHLCV at 1m / 5m / 15m / 1h / 4h / 1d. By condition (market-level) or per-token (each outcome). Pair with trades for VWAP reconciliation.

Trade tape

Every fill on Polymarket and Kalshi. Filter by token, wallet, time range. Ground truth for execution simulation.

Wallet P&L

Realized + unrealized P&L time series for any wallet. The basis for smart-money cohort backtests.

Smart money for a market

Net positioning of profitable wallets in any market right now. Great for confirmation signals.

Leaderboards

Top wallets globally or per-market, sortable by realized profit, ROI, volume, or win rate.

Orderbook tick history

The raw tick stream at every granularity as bulk Parquet — queue position, fill probability, and book replay.

Pending-trade signals (WS)

Mempool detection of fills before they confirm — up to 5 seconds ahead of Polymarket’s RTDS. Used by latency-sensitive strategies.

Backtesting walkthroughs

Three production-grade patterns we’ve written up:

Orderbook replay

Simulate fills against historical L2 state. The gold-standard for capacity-sensitive strategies.

Candle + trade reconciliation

Fast candle-driven backtests with trade-tape validation. Pass 1 is cheap; pass 2 keeps you honest.

Signal backtesting

How to honestly test smart-money, top-holders, and pending-trade signals before sizing into them.

Going live

Once a strategy backtests well, swap REST polling for WebSocket streams using the same data shapes. Read WebSocket Overview for connection patterns, subscription limits, and reconnect handling.

Common quant recipes

Detect smart-money entry

Wallet leaderboard + smart-money endpoint + alert path.

Trade on pending-trade signals

Mempool WS → signal → your venue-native execution.

Monitor any portfolio

Wallet positions + P&L + live fills for any address.

Copy-trade a wallet

Subscribe wallet → mirror each fill. End-to-end.

Data & Signals overview

Full map of every data endpoint, organized by utility.

Best Practices

Pagination, retries, rate-limit handling, WebSocket reconnect logic.