data · data · finance · fx · forex · currency · exchange-rate · conversion · ecb · official-data · reference-rate · fx-rate · currency-conversion · ecb-reference-rate · historical-fx

ECB reference FX conversion

Convert an amount between two supported currencies using one validated ECB daily reference-rate observation. The underlying ECB statistics are available free from the ECB Data Portal; the fee covers bounded retrieval, validation, clearly labelled cross-rate calculation, and x402 delivery.

$0.002 USDCBasex402 v2POST

Pay $0.002 USDC and run in your browser View free result sample

Endpoint

https://apiacre.com/v1/data/ecb-fx-reference

Send the JSON body below. An unpaid request returns HTTP 402 with a PAYMENT-REQUIRED header; an x402-compatible buyer signs the requirement and retries with PAYMENT-SIGNATURE.

Pay $0.002 USDC and run in your browser

Official Coinbase agent path

Coinbase Agentic Wallet can satisfy this x402 request in one command. Running it may pay automatically, so --max-amount is fixed to $0.002 USDC in atomic units. Copying the command does not install, authenticate, sign, or pay; review the request and use a separate low-value wallet before running it.

npx --yes awal@latest x402 pay https://apiacre.com/v1/data/ecb-fx-reference \
  -X POST \
  -d '{"base_currency":"GBP","quote_currency":"USD","amount":"100","on_or_before":null}' \
  --max-amount 2000 \
  --json

Coinbase pay-for-service documentation · Buyer setup and wallet safety

Alternative third-party AgentCash commands

Run check first without payment. Its fetch command may automatically pay up to the exact listed price.

npx --yes agentcash@latest check https://apiacre.com/v1/data/ecb-fx-reference
npx --yes agentcash@latest fetch https://apiacre.com/v1/data/ecb-fx-reference \
  --method POST \
  --header 'content-type: application/json' \
  --body '{"base_currency":"GBP","quote_currency":"USD","amount":"100","on_or_before":null}' \
  --payment-protocol x402 \
  --payment-network base \
  --max-amount 0.002

AgentCash CLI documentation

Input example

{
  "base_currency": "GBP",
  "quote_currency": "USD",
  "amount": "100",
  "on_or_before": null
}

Response shape

View free static sample JSON

{
  "request_id": "018f1f54-7f38-7ba2-8dc3-5f90272d9f1a",
  "service": "data.ecb-fx-reference",
  "version": "1",
  "data": {
    "baseCurrency": "GBP",
    "quoteCurrency": "USD",
    "amount": "100",
    "rate": "1.352573464976",
    "inverseRate": "0.739331375259",
    "convertedAmount": "135.2573465",
    "referenceDate": "2026-08-18",
    "requestedOnOrBefore": null,
    "referenceLagDays": 1,
    "basis": {
      "denomination": "EUR",
      "basePerEur": "0.85585",
      "quotePerEur": "1.1576",
      "formula": "quotePerEur / basePerEur",
      "crossRateDerivedByApiAcre": true,
      "rounding": "half-even; rate 12 decimal places, converted amount 8 decimal places"
    },
    "source": {
      "provider": "European Central Bank",
      "dataset": "EXR daily euro foreign exchange reference rates",
      "seriesKeys": [
        "EXR.D.GBP.EUR.SP00.A",
        "EXR.D.USD.EUR.SP00.A"
      ],
      "requestUrl": "https://data-api.ecb.europa.eu/service/data/EXR/D.GBP+USD.EUR.SP00.A?format=csvdata&detail=dataonly&lastNObservations=10",
      "documentationUrl": "https://data.ecb.europa.eu/help/api/data-examples",
      "reusePolicyUrl": "https://www.ecb.europa.eu/stats/ecb_statistics/governance_and_quality_framework/html/usage_policy.en.html",
      "disclaimerUrl": "https://www.ecb.europa.eu/services/using-our-site/disclaimer/html/index.en.html",
      "attribution": "Source: ECB statistics.",
      "freeSourceNotice": "The underlying ECB statistics are available free of charge from the ECB Data Portal. API Acre charges for bounded retrieval, validation, derived calculation, and x402 delivery\u2014not for exclusive access to those statistics.",
      "statisticsModified": false,
      "derivedValuesClearlyLabelled": true
    },
    "retrievedAt": "2026-08-19T04:00:00+00:00",
    "networkRequestsMade": 1,
    "warnings": [
      "The latest common reference observation is 1 calendar day(s) before the requested cutoff, which can occur on weekends and ECB holidays.",
      "API Acre derived this cross rate by dividing two unmodified ECB euro reference rates; the cross rate and converted amount are calculated values."
    ],
    "limitations": [
      "ECB reference rates are usually published on TARGET business days and are not live, executable, bid, ask, card, cash, remittance, or settlement quotes.",
      "A converted amount is arithmetic evidence only; banks, exchanges, spreads, fees, taxes, and payment timing can produce a different result.",
      "ECB observations can be revised, interrupted, or withdrawn; inspect referenceDate and requestUrl before relying on a result.",
      "Coverage is limited to the explicitly supported active ECB reference-rate currencies published in the input schema."
    ],
    "disclaimer": "Reference data only, not financial advice or a guarantee of an available exchange rate. Source: ECB statistics."
  },
  "meta": {
    "duration_ms": 42,
    "cached": false,
    "sources": [],
    "warnings": [],
    "next_actions": []
  }
}

Try the payment challenge

curl -i -X POST 'https://apiacre.com/v1/data/ecb-fx-reference' \
  -H 'content-type: application/json' \
  --data '{"base_currency":"GBP","quote_currency":"USD","amount":"100","on_or_before":null}'