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Currency & Crypto API – Historical Fiat Exchange Rates
x402
Currency & Crypto API – Historical Fiat Exchange Rates is a paid API for AI agents from currency.payapi.market, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-30).
Returns historical fiat currency exchange rates for a given base currency and date, sourced from the European Central Bank via Frankfurter.
Price / call$0.001
Success—
StatusUnknown
How this service works
Fiat exchange rates (ECB via Frankfurter) and crypto prices (CoinGecko) with x402 payments.
Output
A JSON object containing the base currency code, the requested date, a map of target currency codes to their exchange rates (as decimals), a boolean indicating whether the result was served from cache, and a source attribution string ('ECB via Frankfurter'). Rates are available back to January 4, 1999.
Example use cases
Historical invoice currency reconciliation
“I need to reconcile an invoice that was issued on March 10, 2023 in EUR — what was the USD to EUR exchange rate on that date?”
Travel expense reimbursement calculation
“I have travel expenses from a business trip on November 5, 2022 — what were the GBP and JPY rates against USD on that day so I can calculate reimbursements?”
Historical portfolio valuation
“What were the EUR, CHF, and JPY exchange rates against USD on December 31, 2021? I need to value a foreign currency portfolio at year-end.”
Technical details
Endpoint
POSThttps://currency.payapi.market/rates/historical?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need authoritative historical fiat exchange rates sourced from the European Central Bank for a specific past date, particularly for financial reconciliation, accounting, auditing, or reporting use cases where ECB data is the accepted standard. It is ideal for date-specific lookups going back to 1999. Prefer it over live-rate endpoints when the date in question is in the past, and over crypto endpoints when you need fiat-only rates.
Side effects
- Date before 1999-01-04: ECB data is not available before this date, likely returns an error or empty rates
- Invalid date format: non-YYYY-MM-DD strings will likely cause a validation error
- Unknown currency code: unrecognized ISO 4217 codes in base or symbols may return an error or be silently omitted
- Weekend or holiday date: ECB does not publish rates on non-trading days, may return rates from the nearest prior trading day or an error
- Payment failure: x402 micropayment not satisfied returns 402 response before data is delivered
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| base | string | Base currency ISO 4217 code, e.g. 'USD'. Defaults to USD if omitted. |
| date | string | Date in YYYY-MM-DD format, back to 1999-01-04, e.g. '2024-01-15'. |
| symbols | array | Optional list of target currency codes to restrict the response, e.g. ['EUR', 'GBP']. Omit for all rates. |
Output
Schema · Response
{
"type": "json",
"example": {
"base": "USD",
"date": "2024-01-15",
"rates": {
"EUR": 0.9187,
"GBP": 0.7861
},
"cached": false,
"source": "ECB via Frankfurter"
}
}Tags
x402
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