Foreign exchange
Other FX APIs multiply a rounded mid-market number, cache by amount (so £1 and £100 disagree), and never tell you how many pennies the currency actually uses. This endpoint does the boring bit properly.
What this does
- Fetches the unit ECB euro reference rate for the pair (not a conversion that already includes your amount).
- Multiplies by your amount in full precision.
- Rounds half-up to that currency’s ISO 4217 cash decimals (JPY and KRW are 0, most are 2).
- Returns
converted(cash) andconverted_exact(full float) so a ledger can keep the residue if it must.
Rates come from the European Central Bank via Frankfurter, providers=ECB. They are usually published around 16:00 CET on TARGET working days. Weekends reuse the last working day. This is a reference rate, not a card-scheme or bank-sell quote.
Who it is for
- Invoice PDFs that need a GBP/EUR line that matches ECB publications
- “About £X in dollars” on a UK storefront
- Spreadsheets (
?format=textor?format=csvon/v1/fx/rates) - Historical restatements with
date=YYYY-MM-DD
Try it
https://fetch.li/v1/fx?from=GBP&to=EUR&amount=100
https://fetch.li/v1/fx?from=GBP&to=JPY&amount=50
https://fetch.li/v1/fx?from=USD&to=GBP&amount=250&date=2026-01-02
https://fetch.li/v1/fx?from=GBP&to=EUR&amount=100&format=text
https://fetch.li/v1/fx/currencies
https://fetch.li/v1/fx/rates?base=GBP&format=csv
Example JSON
{
"ok": true,
"answer": "£100.00 = €116.89",
"from": "GBP",
"to": "EUR",
"amount": 100,
"rate": 1.1689,
"inverse": 0.85550432,
"converted": 116.89,
"converted_exact": 116.89,
"minor_units": 2,
"as_of": "2026-08-24",
"provider": "ECB"
}
converted is what you print on an invoice. Do not re-round it. If you chain conversions, start from converted_exact or from amount * rate yourself.
Parameters
| Parameter | Required | Description |
|---|---|---|
from |
Yes | ISO 4217, e.g. GBP |
to |
Yes | ISO 4217, e.g. EUR, JPY |
amount |
No | Default 1 |
date |
No | YYYY-MM-DD only. ECB is daily, not tick data |
format |
No | text returns answer. Rates table accepts csv |
Related
Try it
GET https://fetch.li/v1/fx
Answer
Response