/ DOCUMENTATION
Small, public endpoints for current rates, historical records, conversions, supported currencies, and experimental forecasts.
START HERE
No key is required. Send query parameters over HTTPS and read JSON back. Amounts are numeric, currency codes are uppercase ISO 4217-style codes, and every rate response identifies its source and dates. Rates come from the European Central Bank; non-EUR bases are derived from ECB EUR references by exchange.io.
curl "https://exchangeio.fxzly.my/api/convert?from=USD&to=EUR&amount=100"curl
curl "https://exchangeio.fxzly.my/api/convert?from=USD&to=EUR&amount=100"fetch
fetch('/api/convert?from=USD&to=EUR&amount=100').then(r => r.json())Python
requests.get('/api/convert', params={'from':'USD','to':'EUR','amount':100}).json()Free during this early access period. Add caching on your side when your workload does not need a fresh snapshot per request.
THE API
/api/latest?base=USDReturn the newest available reference snapshot for a base currency.
curl "https://exchangeio.fxzly.my/api/latest?base=USD"{
"base": "USD",
"rates": { "EUR": 0.92, "JPY": 150.12 },
"rate_date": "2026-08-16",
"source": "ecb.europa.eu",
"fetched_at": "2026-08-16T00:04:12.000Z"
}/api/convert?from=USD&to=EUR&amount=100Convert a positive amount using the latest snapshot, or add date for a historical conversion.
curl "https://exchangeio.fxzly.my/api/convert?from=USD&to=EUR&amount=100"{
"from": "USD", "to": "EUR", "amount": 100,
"result": 92, "rate": 0.92,
"rate_date": "2026-08-16",
"source": "ecb.europa.eu",
"fetched_at": "2026-08-16T00:04:12.000Z"
}/api/historical?date=2024-01-15&base=USDRead the stored reference snapshot for an ISO calendar date and base currency.
curl "https://exchangeio.fxzly.my/api/historical?date=2024-01-15&base=USD"{
"base": "USD",
"rates": { "EUR": 0.91, "JPY": 145.48 },
"rate_date": "2024-01-15",
"source": "ecb.europa.eu",
"fetched_at": "2024-01-16T00:04:12.000Z"
}/api/currenciesList supported currency codes with display precision. Response also includes latest source metadata.
curl "https://exchangeio.fxzly.my/api/currencies"/api/forecast?from=USD&to=EUR&horizon=7Return an experimental baseline estimate and range for 1 to 30 days. Response includes model version, training date, and a mandatory disclaimer.
curl "https://exchangeio.fxzly.my/api/forecast?from=USD&to=EUR&horizon=7"/api/healthCheck API availability and rate-service state. Useful for monitoring, not for selecting a rate.
/api/timeseries?start=2024-01-01&end=2024-01-31&base=USDReturn daily rates across an inclusive date range. Add symbols to reduce the response.
curl "https://exchangeio.fxzly.my/api/timeseries?start=2024-01-01&end=2024-01-31&base=USD&symbols=EUR,JPY"/api/fluctuation?start=2024-01-01&end=2024-01-31&base=USDReturn start, end, absolute, and percentage changes for each available symbol.
curl "https://exchangeio.fxzly.my/api/fluctuation?start=2024-01-01&end=2024-01-31&base=USD"/api/batch-convert?from=USD&to=EUR,GBP&amount=100Convert one amount to multiple target currencies.
curl "https://exchangeio.fxzly.my/api/batch-convert?from=USD&to=EUR,GBP&amount=100"/api/metadataReturn names, countries, flags, and symbols for currency codes.
curl "https://exchangeio.fxzly.my/api/metadata"/api/coverageReturn earliest/latest stored dates, data sources, and refresh schedule.
curl "https://exchangeio.fxzly.my/api/coverage"/api/backtest?from=USD&to=EURReturn rolling forecast point count and mean absolute error for a pair.
curl "https://exchangeio.fxzly.my/api/backtest?from=USD&to=EUR"/api/metricsReturn service state and in-process rate cache counters for monitoring.
curl "https://exchangeio.fxzly.my/api/metrics"02 / TIME
Dates use YYYY-MM-DD and mean a UTC calendar day. A request for 2024-01-15 asks for the snapshot labelled January 15, not a rolling 24-hour window.
Omit date from convert for latest data. Future dates are rejected with future_date. Historical availability depends on stored snapshots; missing records return historical_unavailable rather than silently substituting today's rate.
03 / PROVENANCE
rate_date is the date represented by the rate. fetched_at is the UTC timestamp when exchange.io obtained or stored the snapshot. source names the upstream dataset.
Latest data is refreshed on a daily schedule and may be temporarily served from the last known snapshot during upstream trouble. Inspect service state through /api/health and treat fetched_at as the freshness boundary.
FORECAST NOTICE
Forecasts are estimates from a simple historical baseline. They are not predictions, financial advice, or trading signals. Do not use them as the sole basis for a financial decision.
04 / FAILURE
Errors use JSON with error, message, and details. Common codes:
invalid_query — missing, malformed, or non-positive input.unsupported_currency — code is not available from the configured source.future_date — requested date is after today in UTC.historical_unavailable — no stored snapshot matches date and base.forecast_unavailable — insufficient historical pair data.REFERENCE
| Parameter | Type | Meaning |
|---|---|---|
base | string | ISO 4217 base currency; defaults to USD. |
symbols | comma list | Optional response filter. |
start/end | YYYY-MM-DD | Inclusive date range for timeseries and fluctuation. |
amount | positive number | Conversion amount, maximum 1e12. |
date | YYYY-MM-DD | Historical conversion date. |
05 / NEXT