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

# Reference Data API

> Match the same event across venues to one ID, with the venue tickers to trade each side.

<Note>
  The Reference Data API is an enterprise product for institutional customers. It is separate from the retail Oddpool API and is not available on consumer plans. Access requires an institutional agreement and a reference-data-enabled API key. Contact [avi@oddpool.com](mailto:avi@oddpool.com) for access.
</Note>

Kalshi, Polymarket, and other venues each give the same event a different ticker, ID, and question text. The Reference Data API matches them and gives you:

* **one ID per event**: the same game, election, or Fed decision across every venue that lists it
* **one ID per outcome**: each named answer on that event
* **one ID per entity**: the team, person, or party an outcome refers to, with a Wikidata Q-ID
* **the venue tickers** you need to subscribe to live prices on each side

For each matched event, it also tells you where the two venues agree and where they settle differently, so you can size a cross-venue position knowing exactly how fungible the two sides are. That classification is documented on [List matched events](/institutions/reference-data/events/list) and returned on every event.

## Base URL and auth

```text theme={null}
https://api.oddpool.com
```

Every request needs your API key in the `X-API-Key` header and returns JSON:

```bash theme={null}
curl -H "X-API-Key: oddpool_<key>" \
  "https://api.oddpool.com/reference/v2/events?active=true&limit=100"
```

A `401` means the key is missing or unknown; a `403` means the key is valid but doesn't include reference-data access (or its trial has expired).

## Quickstart

<CodeGroup>
  ```bash Resolve a venue ticker theme={null}
  # a Kalshi, Polymarket, or Polymarket US id -> the matched event
  curl -H "X-API-Key: $KEY" \
    "https://api.oddpool.com/reference/v2/events/lookup?venue=kalshi&id=KXSB-27-ARI"
  ```

  ```bash Get an event by ID theme={null}
  curl -H "X-API-Key: $KEY" \
    "https://api.oddpool.com/reference/v2/events/OPI-U3PW57WP"
  ```

  ```bash List live events theme={null}
  # events with markets still trading today
  curl -H "X-API-Key: $KEY" \
    "https://api.oddpool.com/reference/v2/events?active=true&limit=100"
  ```

  ```bash Look up an entity theme={null}
  curl -H "X-API-Key: $KEY" \
    "https://api.oddpool.com/reference/v2/entities/lookup?wikidata_qid=Q22686"
  ```
</CodeGroup>

## Endpoints

<CardGroup cols={2}>
  <Card title="Get Oddpool ID by ticker" icon="right-left" href="/institutions/reference-data/events/lookup">
    Turn a Kalshi, Polymarket, or Polymarket US id into the matched event, with every outcome and venue side.
  </Card>

  <Card title="List matched events" icon="calendar" href="/institutions/reference-data/events/list">
    Page live or historical events, filtered by venue pair and fungibility.
  </Card>

  <Card title="Look up an entity" icon="user" href="/institutions/reference-data/entities/lookup">
    Look up a team, person, or party by Wikidata Q-ID, Oddpool ID, or name.
  </Card>

  <Card title="Search entities" icon="magnifying-glass" href="/institutions/reference-data/entities/list">
    Find entities by substring and kind.
  </Card>
</CardGroup>

## How a response is shaped

Every event response nests four layers, each with its own Oddpool ID:

* **Event** (`OPI`): one real-world resolution, like a game, election, or Fed decision
  * **Outcome** (`OPO`): one named answer on the event, like a team, "Yes", or a price bucket
    * **Venue listing** (`OPL`): one venue's tradeable side of that outcome, the ticker you trade
    * **Entity** (`OPE`): the team, person, or party the outcome refers to

<CardGroup cols={2}>
  <Card title="Supported venues" icon="building-columns" href="/institutions/reference-data/venues">
    The venue tags you can pass to `venue` and `venue_pair`, and how they combine.
  </Card>

  <Card title="Oddpool IDs" icon="fingerprint" href="/institutions/reference-data/oddpool-ids">
    What OPI, OPO, OPL, and OPE identify, how they nest, and why they're safe to cache.
  </Card>

  <Card title="Response fields" icon="list" href="/institutions/reference-data/response-fields">
    Definitions for every field in the event and entity responses, including basis\_class, outcome kinds, and divergence.
  </Card>
</CardGroup>