Historical Rate Coverage

The job

Know how far back a pair can be queried before you build a chart, a backtest, or a data import. Use /v1/history and check the earliest date it returns for each currency.

Coverage by era

This is a guide to availability, not a guarantee that every pair has daily values from the earliest era. The API returns the earliest observation available for each currency. A pair outside its covered range does not have a synthetic value inserted.

Check the first date for a pair

Query a wide range and inspect the first key in rates:

curl "https://api.currency-core.com/v1/history?currency=INR&base=USD&from=1949-01-01&to=1950-12-31" \
  -H "Authorization: Bearer cc_live_your_key" | jq '.rates | keys[0]'

A covered range returns a dense map. The first key is the first available date:

{
  "currency": "INR",
  "base": "USD",
  "interval": "daily",
  "from": "1949-12-30",
  "to": "1950-01-03",
  "rates": {
    "1949-12-30": 4.76,
    "1949-12-31": 4.76,
    "1950-01-01": 4.76,
    "1950-01-02": 4.76,
    "1950-01-03": 4.76
  }
}

The values are illustrative. The shape is the important part: one key per calendar day, including the New Year holiday, with the prior value carried forward. If the result is empty or starts later than expected, the pair has no observation in that window. Dates before a currency’s first quote are absent, not zero.

Plan limits and dense dates

/v1/history is available on every plan. Free can request the last 30 days; an older from returns 403 forbidden. Starter and above can request full history. Inside a covered range, the response is a dense calendar map: weekends and holidays carry the previous trading day forward.

Do not describe 1949 as the start of daily data for all pairs. It is the start of annual parity for two series. For a per-currency view, use /v1/currencies and test the earliest date you actually need.

Related docs

History endpoint, history analysis, currencies, backtesting guide, and the guides hub.