Prediction Market data is currently in beta. It is actively being worked on and improved, but may be unreliable. Polymarket data is live, and Kalshi data will be added soon.At least for the time being, this endpoint requires a Growth or Enterprise plan. Learn more.
Example Query
Example Response (truncated)
Usage Guidelines
Bar data provides time-series OHLC (Open, High, Low, Close) aggregates for individual prediction markets. Each bar represents a time period and includes comprehensive metrics for both outcomes, including price movements, volume, liquidity, bid/ask spreads, and order book depth. Key characteristics:- Market ID formats vary by protocol:
- Polymarket:
<marketAddress>:Polymarket:<exchangeAddress>:<networkId>(e.g.,0x25aa90b3cd98305e849189b4e8b770fc77fe89bccb7cf9656468414e01145d38:Polymarket:0xc5d563a36ae78145c45a50134d48a1215220f80a:137) - Kalshi:
<marketSlug>:Kalshi(e.g.,KXMVECROSSCATEGORY-S2026A4A05B370DF-F1FBA451AA9:Kalshi)
- Polymarket:
- Outcome-level OHLC data: Separate price and liquidity metrics for
outcome0andoutcome1 - Detailed market microstructure: Includes bid/ask prices, spreads, and 2% depth metrics
- Volume breakdown: Track buys, sells, and total volume in USD, collateral tokens, and shares
- Time-series format: Each bar has a timestamp (
t) representing the period start - Multiple resolutions: From 1-minute to 1-week intervals for granular or aggregate analysis
Troubleshooting Tips
Why don't outcome prices sum to 1.00?
Why don't outcome prices sum to 1.00?
In real markets, outcome prices may not sum exactly to 1.00 due to bid/ask spreads, liquidity constraints, and market inefficiencies. The sum typically ranges from 0.98 to 1.02. Large deviations may indicate arbitrage opportunities or data issues.
What's the difference between volumeUsd, volumeShares, and volumeCollateralToken?
What's the difference between volumeUsd, volumeShares, and volumeCollateralToken?
How do I calculate the bid/ask spread?
How do I calculate the bid/ask spread?
Spread =
askUsd.c - bidUsd.c for the close of each bar. A wider spread indicates lower liquidity or higher market uncertainty. Monitor spreads to assess market health and trading conditions.What does twoPercentBidDepthUsd measure?
What does twoPercentBidDepthUsd measure?
This measures the total USD value of bid orders within 2% of the best bid price. It’s a measure of order book depth and liquidity resilience. Higher values mean the market can absorb larger trades without significant price impact.
Why might some outcome fields be null?
Why might some outcome fields be null?
Some fields like
liquidityUsd, bidUsd, and depth metrics may be null for older data or during periods when orderbook snapshots weren’t available. Always check for null values before processing these fields.How should I interpret high/low vs open/close in OHLC?
How should I interpret high/low vs open/close in OHLC?
o(open): Value at the start of the bar periodh(high): Maximum value during the periodl(low): Minimum value during the periodc(close): Value at the end of the period
What does allTimeVolumeUsd represent?
What does allTimeVolumeUsd represent?
This is the cumulative volume for the market from inception up to the close of this bar. It’s useful for tracking market maturity and total activity. Compare it to
volumeUsd in the bar to understand what percentage of total volume occurred in that period.