Czech National Bank Exchange Rate API: Official CZK Rates as JSON

Czech National Bank publishes an official table of exchange rates once per business day — the daily fixing — covering ~33 currencies against the CZK. These are the published central bank rates used for tax filings, customs valuations, audits, and compliant invoicing in Czech Republic — not moving market prices. This guide shows how to pull them as JSON: via a REST endpoint or the zero-dependency czech-national-bank-exchange-rate npm package, with history back to 2016.

What the CNB publishes

• ~33 currencies against the CZK, in one table per business day.
• History back to 2016 — queryable by exact date or as a daily time series.
• The bank's own publication date on every response, so a rate is always citable.
• No weekend or holiday gaps to trip over — requests for non-publication days resolve to the most recent published table and are flagged explicitly.

Why official rates, not market rates

A live mid-market feed answers "what is EUR/CZK trading at right now?" — the right tool for checkouts and dashboards. But accountants, auditors, and tax authorities ask a different question: "which rate were you required to use for this date?" That answer comes from the central bank's published table, and it never changes after publication.

Czech tax practice leans on the CNB fixing: VAT and income-tax conversions in the Czech Republic routinely use the CNB-declared rate.

Get the latest table (REST)

curl "https://allratestoday.com/api/v1/central-bank/cnb/latest" \
  -H "Authorization: Bearer YOUR_API_KEY"

The response is the bank's most recent published table — every currency, the CZK value, and the publication date:

{
  "bank": "cnb",
  "rate_date": "2026-08-01",
  "base": "CZK",
  "rates": [ { "currency": "EUR", "rate": 1.2345, "official": true }, ... ]
}

The latest table is available on every plan, including the free tier (300 requests/month, no credit card). Since the table changes once per business day, caching it locally makes even a small quota go a long way.

The npm SDK

npm install czech-national-bank-exchange-rate

import { getRate, getLatestRates } from 'czech-national-bank-exchange-rate';

// One pair at the official Czech National Bank rate
const pair = await getRate('EUR', 'CZK', { apiKey: 'art_live_...' });
console.log(pair.rate, pair.rate_date);

// The bank's full published table
const table = await getLatestRates({ apiKey: 'art_live_...' });
console.log(table.rate_date, table.rates.length);

Zero dependencies, TypeScript types included, and it runs anywhere fetch exists — Node 18+, Bun, Deno, and edge runtimes.

Historical rates for an invoice date

The most common compliance job: an invoice dated months ago needs the official rate for that date.

import { getRatesForDate, getHistory } from 'czech-national-bank-exchange-rate';

// The official table for an invoice date — weekends/holidays return
// the most recent published date, flagged via published_on_requested_date.
const day = await getRatesForDate('2026-06-30', { apiKey: 'art_live_...' });

// Daily series for one pair
const series = await getHistory(
  { source: 'EUR', target: 'CZK', from: '2026-01-01' },
  { apiKey: 'art_live_...' }
);

Historical dates and time series need a paid plan; the latest table stays free.

Published vs derived pairs

If the CNB does not print a pair directly, the API resolves it from the bank's table — an inverse, or a cross rate via CZK — and flags it derived: true with the method used. Official and computed values are never silently mixed, which is exactly the distinction an auditor will ask about.

FAQ

Does Czech National Bank have an official exchange rate API?

Czech National Bank publishes its official rates on its website, but not always in a developer-friendly form. AllRatesToday serves the bank's published table as clean JSON — ~33 currencies against the CZK, with history back to 2016 — via REST or the czech-national-bank-exchange-rate npm package. The latest table is free.

How often do Czech National Bank rates update?

Once per business day. These are published reference rates, not moving market prices — the table changes when the CNB publishes a new one, and every API response carries the bank's own publication date so you can cite it.

Can I get the Czech National Bank rate for a past date, like an invoice date?

Yes. The /central-bank/cnb/rates-for-date endpoint returns the official table for any date back to 2016. Weekends and holidays resolve to the most recent published table and are flagged, so your audit trail stays honest. Historical dates require a paid plan; latest rates are free.