> ## 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.
# onPredictionEventBarsUpdated
> Live-streamed bar chart data to track price changes over time for a prediction event.
**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.
## GraphQL
```
type Subscription {
# Requires a Growth or Enterprise plan.
onPredictionEventBarsUpdated(
eventId: String!
): OnPredictionEventBarsUpdatedResponse
}
type PredictionEventBarOhlc {
o: String!
h: String!
l: String!
c: String!
}
type PredictionEventBar {
t: Int!
volumeUsd: String!
buyVolumeUsd: String
sellVolumeUsd: String
totalVolumeUsd: String!
venueVolumeUsd: String
volumeCollateralToken: String
buyVolumeCollateralToken: String
sellVolumeCollateralToken: String
totalVolumeCollateralToken: String
venueVolumeCollateralToken: String
trades: Int!
uniqueTraders: Int
lastEventTimestamp: Int!
liquidityUsd: PredictionEventBarOhlc
liquidityCollateralToken: PredictionEventBarOhlc
openInterestUsd: PredictionEventBarOhlc
openInterestCollateralToken: PredictionEventBarOhlc
}
type PredictionEventResolutionBarData {
min1: PredictionEventBar
min5: PredictionEventBar
min15: PredictionEventBar
min30: PredictionEventBar
hour1: PredictionEventBar
hour4: PredictionEventBar
hour12: PredictionEventBar
day1: PredictionEventBar
week1: PredictionEventBar
}
type OnPredictionEventBarsUpdatedResponse {
eventId: String!
bars: PredictionEventResolutionBarData!
}
```
## Subscription example
Test this query in the Explorer →
```graphql theme={null}
subscription {
onPredictionEventBarsUpdated(eventId: "67284:Polymarket:0xc5d563a36ae78145c45a50134d48a1215220f80a:137") {
bars {
min1 {
t
volumeUsd
buyVolumeUsd
sellVolumeUsd
totalVolumeUsd
venueVolumeUsd
volumeCollateralToken
trades
uniqueTraders
lastEventTimestamp
liquidityUsd {
o
h
l
c
}
openInterestUsd {
o
h
l
c
}
}
min5 {
t
volumeUsd
trades
uniqueTraders
liquidityUsd {
o
h
l
c
}
}
min15 {
t
volumeUsd
trades
}
hour1 {
t
volumeUsd
totalVolumeUsd
trades
}
hour4 {
t
volumeUsd
}
day1 {
t
volumeUsd
totalVolumeUsd
}
}
}
}
```
```json Example Response theme={null}
{
"data": {
"onPredictionEventBarsUpdated": {
"bars": {
"min1": {
"t": 1773357360,
"volumeUsd": "1047.043738",
"buyVolumeUsd": "1046.940304",
"sellVolumeUsd": "0.103434",
"totalVolumeUsd": "183698948.904681",
"venueVolumeUsd": "350603420.708316",
"volumeCollateralToken": "1047.10344",
"trades": 5,
"uniqueTraders": 2,
"lastEventTimestamp": 1773357373,
"liquidityUsd": {
"o": "40568747.579197",
"h": "40569107.283499",
"l": "40568639.455529",
"c": "40568771.326025"
},
"openInterestUsd": {
"o": "34058066.149446",
"h": "34058066.149446",
"l": "34058066.149446",
"c": "34058066.149446"
}
},
"min5": {
"t": 1773357300,
"volumeUsd": "3347.885241",
"trades": 10,
"uniqueTraders": 3,
"liquidityUsd": {
"o": "40571553.036979",
"h": "40571553.036979",
"l": "40568639.455529",
"c": "40568771.326025"
}
},
"min15": {
"t": 1773357300,
"volumeUsd": "3347.885241",
"trades": 10
},
"hour1": {
"t": 1773356400,
"volumeUsd": "29290.703467",
"totalVolumeUsd": "183698948.904681",
"trades": 72
},
"hour4": {
"t": 1773345600,
"volumeUsd": "129468.523663"
},
"day1": {
"t": 1773273600,
"volumeUsd": "8580175.57018",
"totalVolumeUsd": "183698948.904681"
}
}
}
}
}
```
### Usage Guidelines
* **Event ID format** varies by platform:
* **Polymarket**: `:Polymarket::` (e.g., `67284:Polymarket:0xc5d563a36ae78145c45a50134d48a1215220f80a:137`)
* **Kalshi**: `:Kalshi` (e.g., `KXMVESPORTSMULTIGAMEEXTENDED-S2026350C4EF9BCE:Kalshi`)
* Subscribe using `eventId` to receive live bar chart data for a prediction event
* Bars are provided across multiple resolutions simultaneously: `min1`, `min5`, `min15`, `min30`, `hour1`, `hour4`, `hour12`, `day1`, and `week1`
* Updates stream whenever new trading activity occurs, recalculating affected bars
### Troubleshooting Tips
Choose based on your timeframe: `min1` for tick-by-tick updates, `min5` or `min15` for short-term charts (1-hour view), `hour1` or `hour4` for medium-term (1-day to 1-week view), and `day1` or `week1` for long-term historical views. Request only the resolutions you need to reduce data volume.
The `t` field is the Unix timestamp marking the start of that bar's time period. For example, a 5-minute bar with `t: 1710345600` covers the period from that timestamp to 5 minutes later (1710345900). Bars are aligned to clean intervals (e.g., :00, :05, :10 for 5-minute bars).
OHLC (Open, High, Low, Close) shows the range and direction of liquidity or open interest during that bar. `o` is the value at the bar's start, `h` is the maximum, `l` is the minimum, and `c` is the value at the bar's end. This helps visualize how capital flow changed over time.
`volumeUsd` is the trading volume that occurred during that specific bar period, while `totalVolumeUsd` is the cumulative all-time volume for the event up to that bar. Use `volumeUsd` for bar charts and `totalVolumeUsd` to show total market size.
Bars update in real-time as trades occur. When a new trade happens, all affected bars (across all resolutions) are recalculated and pushed via the subscription. High-activity events may send updates multiple times per second during peak trading.
No. Bars only exist if there was activity during that time period. For events with sparse trading, you may receive null values for smaller resolutions (e.g., `min1` or `min5`) while larger resolutions (e.g., `hour1`, `day1`) have data. Check for null before rendering.
Bars are considered "complete" once their time period has passed. For example, a 1-minute bar starting at 12:00:00 is complete after 12:01:00. You can update your chart in real-time for the current incomplete bar and treat completed bars as final. Use `lastEventTimestamp` to determine freshness.