> ## Documentation Index
> Fetch the complete documentation index at: https://docs.codex.io/llms.txt
> Use this file to discover all available pages before exploring further.

# onPredictionMarketBarsUpdated

> Live-streamed bar chart data to track price changes over time for a prediction market.

<Info>
  **Prediction Market data is currently in beta**. It is actively being worked on and improved, but may be unreliable. Polymarket and Kalshi data are live.
</Info>

<div data-generated>
  ## GraphQL

  ```
  type Subscription {
    # Requires a Growth or Enterprise plan.
    onPredictionMarketBarsUpdated(
      marketId: String!
    ): OnPredictionMarketBarsUpdatedResponse
  }

  type PredictionMarketBarOhlc {
    o: String!
    h: String!
    l: String!
    c: String!
  }

  type PredictionOutcomeBar {
    venueOutcomeId: String!
    trades: Int
    buys: Int
    sells: Int
    volumeShares: String
    buyVolumeShares: String
    sellVolumeShares: String
    volumeUsd: String
    buyVolumeUsd: String
    sellVolumeUsd: String
    volumeCollateralToken: String
    buyVolumeCollateralToken: String
    sellVolumeCollateralToken: String
    priceUsd: PredictionMarketBarOhlc
    priceCollateralToken: PredictionMarketBarOhlc
    liquidityUsd: PredictionMarketBarOhlc
    liquidityCollateralToken: PredictionMarketBarOhlc
    bidUsd: PredictionMarketBarOhlc
    bidCollateralToken: PredictionMarketBarOhlc
    askUsd: PredictionMarketBarOhlc
    askCollateralToken: PredictionMarketBarOhlc
    twoPercentBidDepthUsd: PredictionMarketBarOhlc
    twoPercentBidDepthCollateralToken: PredictionMarketBarOhlc
    twoPercentAskDepthUsd: PredictionMarketBarOhlc
    twoPercentAskDepthCollateralToken: PredictionMarketBarOhlc
  }

  type PredictionMarketBar {
    t: Int!
    volumeUsd: String
    volumeCollateralToken: String
    volumeShares: String
    uniqueTraders: Int
    lastEventTimestamp: Int
    trades: Int
    allTimeVolumeUsd: String
    allTimeVenueVolumeUsd: String
    allTimeVolumeCollateralToken: String
    allTimeVenueVolumeCollateralToken: String
    openInterestUsd: PredictionMarketBarOhlc
    outcome0: PredictionOutcomeBar
    outcome1: PredictionOutcomeBar
  }

  type PredictionMarketResolutionBarData {
    min1: PredictionMarketBar
    min5: PredictionMarketBar
    min15: PredictionMarketBar
    min30: PredictionMarketBar
    hour1: PredictionMarketBar
    hour4: PredictionMarketBar
    hour12: PredictionMarketBar
    day1: PredictionMarketBar
    week1: PredictionMarketBar
  }

  type OnPredictionMarketBarsUpdatedResponse {
    marketId: String!
    bars: PredictionMarketResolutionBarData!
  }
  ```
</div>

## Subscription example

<a href="/explore" target="_blank" rel="noopener noreferrer">Test this query in the Explorer →</a>

```graphql theme={null}
subscription {
  onPredictionMarketBarsUpdated(marketId: "0x25aa90b3cd98305e849189b4e8b770fc77fe89bccb7cf9656468414e01145d38:Polymarket:0xc5d563a36ae78145c45a50134d48a1215220f80a:137") {
    bars {
      min1 {
        t
        volumeUsd
        volumeCollateralToken
        volumeShares
        uniqueTraders
        trades
        lastEventTimestamp
        allTimeVolumeUsd
        openInterestUsd {
          o
          h
          l
          c
        }
        outcome0 {
          venueOutcomeId
          trades
          buys
          sells
          volumeShares
          buyVolumeShares
          sellVolumeShares
          volumeUsd
          buyVolumeUsd
          sellVolumeUsd
          priceUsd {
            o
            h
            l
            c
          }
          liquidityUsd {
            o
            h
            l
            c
          }
        }
        outcome1 {
          venueOutcomeId
          trades
          volumeShares
          volumeUsd
          priceUsd {
            o
            h
            l
            c
          }
        }
      }
      hour1 {
        t
        volumeUsd
        allTimeVolumeUsd
        outcome0 {
          volumeUsd
          priceUsd {
            o
            h
            l
            c
          }
        }
      }
      day1 {
        t
        volumeUsd
        allTimeVolumeUsd
        outcome0 {
          priceUsd {
            o
            c
          }
        }
      }
    }
  }
}
```

```json Example Response theme={null}
{
  "data": {
    "onPredictionMarketBarsUpdated": {
      "bars": {
        "min1": {
          "t": 1773357420,
          "volumeUsd": "1.999905",
          "volumeCollateralToken": "2",
          "volumeShares": "1000000000",
          "uniqueTraders": 1,
          "trades": 1,
          "lastEventTimestamp": 1773357437,
          "allTimeVolumeUsd": "124698566.079866",
          "openInterestUsd": {
            "o": "8218458.66957",
            "h": "8218458.66957",
            "l": "8218458.66957",
            "c": "8218458.66957"
          },
          "outcome0": {
            "venueOutcomeId": "54073086346734626735797775941991553522163760164405051969883391401961188364109:Polymarket:0xc5d563a36ae78145c45a50134d48a1215220f80a:137",
            "trades": 1,
            "buys": 1,
            "sells": 0,
            "volumeShares": "1000000000",
            "buyVolumeShares": "1000000000",
            "sellVolumeShares": "0",
            "volumeUsd": "1.999905",
            "buyVolumeUsd": "1.999905",
            "sellVolumeUsd": "0",
            "priceUsd": {
              "o": "0.002",
              "h": "0.002",
              "l": "0.002",
              "c": "0.002"
            },
            "liquidityUsd": {
              "o": "7899206.931142",
              "h": "7899206.931142",
              "l": "7897876.523427",
              "c": "7897876.523427"
            }
          },
          "outcome1": {
            "venueOutcomeId": "111080671036126109659854287535401661966194360665829017654832975124868412594547:Polymarket:0xc5d563a36ae78145c45a50134d48a1215220f80a:137",
            "trades": 0,
            "volumeShares": "0",
            "volumeUsd": "0",
            "priceUsd": {
              "o": "0.998954",
              "h": "0.998954",
              "l": "0.998954",
              "c": "0.998954"
            }
          }
        },
        "hour1": {
          "t": 1773356400,
          "volumeUsd": "6583.556291",
          "allTimeVolumeUsd": "124698566.079866",
          "outcome0": {
            "volumeUsd": "1.999905",
            "priceUsd": {
              "o": "0.002",
              "h": "0.002",
              "l": "0.002",
              "c": "0.002"
            }
          }
        },
        "day1": {
          "t": 1773273600,
          "volumeUsd": "2790868.223935",
          "allTimeVolumeUsd": "124698566.079866",
          "outcome0": {
            "priceUsd": {
              "o": "0.002",
              "c": "0.002"
            }
          }
        }
      }
    }
  }
}
```

### Usage Guidelines

* **Market ID format**:
  * **Polymarket**: `<marketAddress>:Polymarket:<exchangeAddress>:<networkId>` (e.g., `0x25aa90b3cd98305e849189b4e8b770fc77fe89bccb7cf9656468414e01145d38:Polymarket:0xc5d563a36ae78145c45a50134d48a1215220f80a:137`)
  * **Kalshi**: `<marketSlug>:Kalshi` (e.g., `KXMVECROSSCATEGORY-S2026A4A05B370DF-F1FBA451AA9:Kalshi`)
* Subscribe using `marketId` to receive live bar chart data for a specific prediction market (outcome)
* Price OHLC values range from 0.00 to 1.00, representing the probability (0% to 100%) of that outcome
* Updates stream in real-time as trades occur on the specific market

### Troubleshooting Tips

<AccordionGroup>
  <Accordion title="What's the difference between market bars and event bars?">
    Market bars ([`onPredictionMarketBarsUpdated`](/api-reference/subscriptions/onpredictionmarketbarsupdated)) track individual outcomes with price OHLC data, while event bars ([`onPredictionEventBarsUpdated`](/api-reference/subscriptions/onpredictioneventbarsupdated)) aggregate data across all outcomes. Use market bars for charting outcome probabilities and event bars for overall event activity.
  </Accordion>

  <Accordion title="How do I interpret outcome0, outcome1, etc.?">
    Each `outcomeX` field represents one possible result in the market. For binary markets, `outcome0` is typically "Yes" and `outcome1` is "No". For multi-outcome markets, there may be `outcome2`, `outcome3`, etc. Check the market metadata via `getPredictionMarkets` to see outcome labels.
  </Accordion>

  <Accordion title="Why do outcome prices not always sum to 1.00?">
    In theory, all outcome prices should sum to 1.00 (representing 100% probability across all possibilities). In practice, prices may not sum exactly to 1.00 due to spreads, liquidity, and arbitrage opportunities. Large deviations indicate market inefficiency or low liquidity.
  </Accordion>

  <Accordion title="What's the difference between volumeShares and volumeUsd?">
    `volumeShares` tracks the number of outcome shares traded, while `volumeUsd` tracks the USD value of those shares. Since share prices fluctuate (e.g., 0.65 per share), the same number of shares has different USD values over time. Use `volumeShares` for share-based analysis and `volumeUsd` for monetary analysis.
  </Accordion>

  <Accordion title="Which resolution should I use for price charts?">
    For real-time price tracking, use `min1` or `min5`. For intraday charts, use `min15` or `hour1`. For daily overviews, use `hour4` or `day1`. Higher resolutions reduce noise but may miss short-term price movements. Request only needed resolutions to minimize data transfer.
  </Accordion>

  <Accordion title="How do I track buy vs. sell pressure?">
    Use the `buys` and `sells` counts along with `buyVolumeUsd` and `sellVolumeUsd` within each outcome's data. More buys than sells (or higher buy volume) indicates bullish sentiment on that outcome, while the opposite suggests bearish sentiment.
  </Accordion>
</AccordionGroup>