Skip to main content
In this recipe we’ll show you how to fetch and render prediction market chart data at three levels: individual market outcome charts, event-level aggregated charts, and multi-market comparison charts within an event.

Prediction market charts differ from token charts: instead of a single price, you have dual outcome probabilities, bid/ask spreads, and market-level metrics like open interest. Three chart queries are available:
  • predictionMarketBars: single market, per-outcome OHLC
  • predictionEventBars: event-level aggregated volume/liquidity/OI
  • predictionEventTopMarketsBars: multi-market probability comparison
All support resolutions: min1, min5, min15, min30, hour1, hour4, hour12, day1, week1.

​
Step 1: Single Market Outcome Charts

The core chart for any prediction market detail page. It shows how each outcome’s probability has moved over time with full OHLC data. Use predictionMarketBars to fetch per-outcome price, liquidity, bid/ask, and volume data.
You will need a market ID to fetch charts. Use filterPredictionMarkets to grab a market ID.
Chart types you can render from this data:Outcome probability (candlestick or line):
  • Use outcome0.priceCollateralToken / outcome1.priceCollateralToken for OHLC candlestick charts
  • The close price (c) represents the current implied probability (e.g., 0.65 = 65%)
  • For a simpler line chart, just plot the c (close) values over time
Bid/Ask spread (dual line):
  • Plot outcome0.bidCollateralToken.c and outcome0.askCollateralToken.c as two lines
  • The gap between them is the spread. Tighter = more liquid/efficient market
Volume (bar chart):
  • volumeUsd at the market level for total volume per bar
  • Per-outcome volume with outcome0.volumeUsd / outcome1.volumeUsd
  • Buy/sell breakdown with buyVolumeUsd / sellVolumeUsd
Open interest (OHLC):
  • openInterestUsd at the market level shows total capital at risk
Activity (line):
  • trades and uniqueTraders per bar
Additional parameters:
  • countback: Instead of from, specify “give me the last N bars from to”, which is useful for “show last 100 candles”
  • removeEmptyBars: Skip bars with no trading activity (useful for illiquid markets)

​
Step 2: Multi-Market Probability Comparison

The signature prediction market chart: multiple outcome lines on one chart, like Polymarket’s multi-candidate probability view. Use predictionEventTopMarketsBars to get bars for the top markets in an event in a single request.

How to use this data:
  • Returns OHLC bars for up to 10 markets in a single request
  • Each market in marketBars has its own bars array
  • Plot outcome0.priceCollateralToken.c for each market as a separate colored line, labeled with predictionMarket.label
  • Ranking options: rankBy for market-level attributes (volumeUsd1w, trendingScore24h, etc.) or rankByOutcome + rankByOutcomeAttribute for outcome-level (bestAskCT, lastPriceUsd, etc.)
  • marketIds overrides ranking. Use it when you want specific markets regardless of rank

​
Step 3: Event-Level Aggregated Charts

Shows aggregated activity across ALL markets in an event. This is useful for volume, liquidity, and open interest charts at the event level. Use predictionEventBars.

Chart types from this data:
  • Volume bar chart: volumeUsd per bar, optionally split into buyVolumeUsd / sellVolumeUsd for buy/sell pressure visualization
  • Liquidity area chart: liquidityUsd OHLC. Use c for a simple line, or shade between l and h for a range
  • Open interest line: openInterestUsd OHLC. Shows total capital committed across all markets
  • Activity line: trades and uniqueTraders per bar
  • Cumulative volume: totalVolumeUsd is the running total
This query does NOT include per-outcome price data. Use predictionEventTopMarketsBars for that.

​
Step 4: Rendering with a Chart Library

Transform the API response into chart-ready data. This approach works with any library (lightweight-charts, TradingView, Chart.js, etc.):

Candlestick data (for outcome prices):
// Transform outcome OHLC bars for a candlestick chart
const candlestickData = bars.map(bar => ({
  time: bar.t,   // unix timestamp
  open: parseFloat(bar.outcome0.priceCollateralToken.o),
  high: parseFloat(bar.outcome0.priceCollateralToken.h),
  low: parseFloat(bar.outcome0.priceCollateralToken.l),
  close: parseFloat(bar.outcome0.priceCollateralToken.c),
}));
Multi-line data (for probability comparison):
// Transform multiple markets into line series
const series = marketBars.map(mb => ({
  label: mb.predictionMarket.label,
  data: mb.bars.map(bar => ({
    time: bar.t,
    value: parseFloat(bar.outcome0.priceCollateralToken.c),
  })),
}));
Volume bars:
// Transform volume data for bar chart overlay
const volumeData = bars.map(bar => ({
  time: bar.t,
  value: parseFloat(bar.volumeUsd),
  color: parseFloat(bar.buyVolumeUsd) > parseFloat(bar.sellVolumeUsd)
    ? '#22c55e'  // green = net buying
    : '#ef4444', // red = net selling
}));

​
Step 5: Resolution Selection

Time range displayedRecommended resolution
Last hourmin1
Last 4 hoursmin5
Last 24 hoursmin15 or min30
Last weekhour1
Last monthhour4 or hour12
Last 3 monthsday1
All timeday1 or week1
  • Higher resolutions (min1, min5) give more granular data but return more bars
  • For markets with low activity, use removeEmptyBars: true to skip empty candles
  • Use countback instead of from when you want a fixed number of bars regardless of time range

​
Putting It All Together

Recommended chart layout for a prediction event page:
  1. Top chart: Multi-market probability lines via predictionEventTopMarketsBars, the hero visualization
  2. Below: Volume bar chart via predictionEventBars, showing overall event activity
  3. Drill-down: When user clicks a specific market, show its detailed OHLC chart via predictionMarketBars with metric selector (price, liquidity, bid/ask, volume, OI)
All three queries accept the same resolution values, so a single resolution picker can control all charts on the page.
Collateral Token (CT) vs USD: CT values (e.g., priceCollateralToken) are preferred for prediction markets since the collateral is typically a stablecoin. USD values include exchange rate fluctuations.Implied probability: For stablecoin-collateral markets, priceCollateralToken.c = 0.65 means the market implies a 65% probability.OHLC fields: o = open, h = high, l = low, c = close. Standard candlestick format. All values are strings that should be parsed to floats.Timestamps: The t field is a unix timestamp in seconds. Chart libraries may need milliseconds, so multiply by 1000.Empty bars: Illiquid markets may have bars with no trades. Use removeEmptyBars to skip them, or fill forward with the previous bar’s close value for continuous lines.
Check out the related chart endpoints in their API reference pages: