Polymarket & Kalshi backtesting and historical order-book data.

Recorded full-depth books for Polymarket, Kalshi, and Limitless, delivered through REST and WebSocket with documented coverage and venue-specific cadence.

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640M
order books captured
90+
days history
7
assets
REST + WS
delivery
Backtest Lab

Find out whether an idea has an edge, no pipeline needed. The Backtest Lab runs the whole test in the browser, on the real recorded book.

Paper trading

A backtest is a claim about the past. Paper trading tests it on markets still to come: virtual cash, real prices, a record you cannot fake.

Prefer files to API calls?

The recorded market.
Ready for your own stack.

Polymarket and Kalshi daily Parquet datasets. Inspect the schema and synthetic samples, choose UTC dates, and see the price before you buy.

Browse bulk data

Most feeds stop at the last price.

A single number. It says nothing about the size waiting to fill.

We capture every level, both sides.

The full bid and ask ladder, with the size resting at every price.

Recorded at every change, forever.

Every frame stored, so a backtest fills against the liquidity that was really there.

This is where DepthFeed comes in.

The book, not just the last price.

The full book, every level, both sides

  • Every level, with size
  • Both sides of the book
  • Captured at every change

Recorded on every book event

  • Every book event stored
  • Never sampled
  • Short markets stay testable

One REST API for latest and history

  • Latest and past snapshots
  • JSON, epoch-millis stamps
  • Keyset pagination

Underlying prices, time-aligned

  • Binance spot and futures
  • Chainlink settlement marks
  • Joined on epoch millis

The order book as it was, on every prediction market

DepthFeedStudio

Backtest on the full order book.

Replay the book as it was.

Size the slippage first.

Then pull it over the API.

View Studio

Backtests

Liquidity

Slippage

Market catalogue

For

  • Quant researchers
  • Systematic traders
  • Market makers
  • Prop desks
  • Data scientists
  • Risk teams
  • Academic researchers
  • Strategy builders
  • Trading bots
  • Anyone testing an edge

Full order-book depth, captured continuously. One schema across every venue we cover.

Polymarket

Start backtesting on real depth.

Start free