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

# FX

> Reference rates plus returns, realised volatility and trend.

ECB reference rates for major and minor pairs, with derived measures computed on top.

## Calling it

<CodeGroup>
  ```bash cURL theme={"dark"}
  curl -H "x-api-key: $QUANTORA_API_KEY" \
    "https://api.financialdatapi.com/observations/latest?entity_id=instrument_EURUSD"
  ```

  ```python Python theme={"dark"}
  latest = requests.get(
      "https://api.financialdatapi.com/observations/latest",
      params={"entity_id": "instrument_EURUSD"},
      headers={"x-api-key": KEY},
  ).json()["data"]
  ```
</CodeGroup>

History for one pair:

<CodeGroup>
  ```bash cURL theme={"dark"}
  curl -H "x-api-key: $QUANTORA_API_KEY" \
    "https://api.financialdatapi.com/observations?entity_id=instrument_EURUSD&indicator_id=fx_spot&limit=500&sort=period&order=desc"
  ```

  ```python Python theme={"dark"}
  history = requests.get(
      "https://api.financialdatapi.com/observations",
      params={"entity_id": "instrument_EURUSD", "indicator_id": "fx_spot", "limit": 500},
      headers={"x-api-key": KEY},
  ).json()["data"]
  ```
</CodeGroup>

## What is served

| Measure             | Notes                                           |
| ------------------- | ----------------------------------------------- |
| Spot                | ECB reference rate, one fixing per business day |
| Returns             | Over standard windows                           |
| Realised volatility | Computed from the reference series              |
| Trend               | Momentum measures over standard windows         |

The derived measures carry `sourceTier: "financialdatapi_derived"`, so it is always
visible which figures are the publisher's and which are ours.

<Note>
  ECB reference rates are a **daily fixing**, not a live quote. They are published once
  each business day, around 16:00 CET, and are the right input for research and the wrong
  input for execution.
</Note>

## Quoting convention

Pairs follow the ECB's convention, which is euro base where the euro is involved.
`EURUSD` is dollars per euro. Inverting a pair to match a different convention is your
call to make explicitly rather than something the API guesses at.

Weekends and target holidays have no fixing. Gaps in the series are the calendar, not
missing data.