---
title: "Get Event History"
method: GET
path: "/api/v1/events/{source}/{event_id}/history"
tags: ["events"]
---

# Get Event History

`GET /api/v1/events/{source}/{event_id}/history`

## Request

- Base URL: `https://api.pdata.world`
- URL: `https://api.pdata.world/api/v1/events/{source}/{event_id}/history`
- Auth: none declared

Per-market probability + 24h-volume history for an event, downsampled to a chosen range. Powers the detail-page charts. A Kalshi market ticker passed in place of the event id (for example `KXU3MAX-30-10` for event `KXU3MAX-30`) answers 307 to its event's history with `market_id` set.

## Path parameters

- `source` string, required: Platform id, e.g. kalshi.
- `event_id` string, required: Event id native to the source. A market ticker that extends its event id redirects to that event.

## Query parameters

- `range` '24h' | '7d' | '30d' | 'all'
- `market_id` string, nullable: Narrow/union one market into the set.
- `limit` integer: Top-K markets in detail order.

## Response `200`

Successful Response

- EventHistoryOut
  - `source` string, required: Venue the event comes from.
  - `event_id` string, required: The venue's own event id; unique within `source`.
  - `range` '24h' | '7d' | '30d' | 'all', required: The window covered: the last 24h, 7d or 30d, or all (back to pdata's first snapshot of the market; history starts May 2026).
  - `bucket_seconds` integer, required: Nominal width of one point's time bucket, in seconds: 1800 for 24h, 7200 for 7d, 28800 for 30d, 86400 for all. Long series are thinned to at most 120 points.
  - `series` MarketHistorySeries[]: One series per market: the event's top `limit` markets in the order the event endpoint lists them, plus `market_id` when it was asked for.
    - `source` string, required: Venue the market comes from.
    - `market_id` string, required: The venue's own market id; unique within `source`.
    - `name` string, nullable: The outcome's label: the venue's short outcome title where it sets one, else the market's full question.
    - `points` HistoryPoint[]: Points oldest first. pdata records a snapshot when a market changes, so a quiet market has gaps. Snapshots older than 7 days are kept as 12-hour buckets.
      - `t` string, date-time, required: Start of the point's time bucket (UTC). The point carries the last snapshot pdata recorded inside the bucket.
      - `probability` number, nullable: Implied probability of the market's first outcome (usually YES), in [0, 1]. Null in `event_volume` points.
      - `volume_24hr` number, nullable: The rolling 24-hour trading volume at that snapshot. Venue-reported, in the venue's own unit and not converted across venues: shares for Polymarket and contracts for Kalshi (each pays $1 at resolution), play-money mana for Manifold, and each other venue's figure as it reports it. Null where the venue reports no per-market volume.
  - `event_volume` HistoryPoint[]: The event's own 24-hour volume over time, filled only when no market series carries volume (Gemini reports volume per event, not per contract). Empty for every other venue.
    - `t` string, date-time, required: Start of the point's time bucket (UTC). The point carries the last snapshot pdata recorded inside the bucket.
    - `probability` number, nullable: Implied probability of the market's first outcome (usually YES), in [0, 1]. Null in `event_volume` points.
    - `volume_24hr` number, nullable: The rolling 24-hour trading volume at that snapshot. Venue-reported, in the venue's own unit and not converted across venues: shares for Polymarket and contracts for Kalshi (each pays $1 at resolution), play-money mana for Manifold, and each other venue's figure as it reports it. Null where the venue reports no per-market volume.
  - `_meta` ResponseMetaList: Agent metadata for list/aggregate responses (no cite_as).
    - `attribution` string: Who aggregated this data, under which licence, and whose data it is.
    - `canonical_url` string, required: Stable URL for this resource: the pdata.world page, or the API URL for list responses.
    - `as_of` string, date-time: When this response was generated (UTC).
    - `docs` string: API documentation.

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/pdata/apis/pdata-backend.md) · [All operations](https://skmtc.dev/pdata/apis/pdata-backend/llms.txt) · [OpenAPI document](https://skmtc.dev/pdata/apis/pdata-backend/revisions/4c9bf3856786?raw)