# Czech National Bank (CNB) FX API > Live official Czech foreign-exchange fixing, served straight from the Czech National Bank's open API — no key, nothing cached. The CNB declares one official rate per currency every working day. The rates endpoint returns the whole daily fixing — around 30 world currencies against the koruna (CZK), each with the country, the unit amount it is quoted per and the rate — and accepts a date so you can pull the official fixing for any past working day. The currency endpoint returns one currency's rate, normalised to the koruna value of a single unit, for the latest day or a chosen date — the US dollar fixed around 21 koruna in mid-2026. The convert endpoint turns an amount from any currency into any other, crossed through the koruna at the official fixing, on the latest day or a historical date. The history endpoint returns a currency's official rate over the last several working days. Everything is the central bank's own published fixing, live, nothing stored. This is the Czech koruna FX layer for any forex, payments, e-commerce, accounting or treasury app operating in Czechia and Central Europe — and a clean source of historical FX by date. Distinct from the ECB, Fed, Bank of Canada, Norges Bank, Bank of England, Brazil and Poland central-bank APIs — this is the koruna and the CNB daily fixing, queryable by date. 5 endpoints, no key on our side. ## Authentication All requests require your oanor API key in the `x-oanor-key` header. Get one at https://www.oanor.com/developer/keys. ```bash curl -H "x-oanor-key: oanor_live_…" "https://api.oanor.com/cnb-api/..." ``` ## Pricing - **Free** (Free) — 2,000 calls/Mo, 2 req/s - **Starter** ($9/Mo) — 30,000 calls/Mo, 6 req/s - **Pro** ($23/Mo) — 170,000 calls/Mo, 15 req/s - **Mega** ($56/Mo) — 900,000 calls/Mo, 40 req/s ## Endpoints ### CNB #### `GET /v1/convert` — Convert between currencies via CZK **Parameters:** - `from` (query, required, string) — Source currency Example: `USD` - `to` (query, required, string) — Target currency Example: `EUR` - `amount` (query, optional, string) — Amount (default 1) Example: `100` - `date` (query, optional, string) — YYYY-MM-DD (optional) **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/cnb-api/v1/convert?from=USD&to=EUR&amount=100" ``` **Response:** ```json { "data": { "to": "EUR", "via": "CZK", "from": "USD", "note": "crossed through CZK at the CNB official fixing", "rate": 0.866749, "amount": 100, "result": 86.674917, "source": "Česká národní banka", "to_czk": 24.24, "from_czk": 21.01, "valid_for": "2026-06-08" }, "meta": { "timestamp": "2026-06-09T11:38:19.897Z", "request_id": "a1ca005d-507e-4c87-b5cf-a40c18f716c8" }, "status": "ok", "message": "Conversion retrieved successfully", "success": true } ``` #### `GET /v1/currency` — One currency rate (latest or by date) **Parameters:** - `code` (query, required, string) — Currency code Example: `USD` - `date` (query, optional, string) — YYYY-MM-DD for a past working day **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/cnb-api/v1/currency?code=USD" ``` **Response:** ```json { "data": { "base": "CZK", "code": "USD", "note": "USD in CZK: 1 USD = unit_rate CZK", "rate": 21.01, "amount": 1, "source": "Česká národní banka", "country": "USA", "currency": "dollar", "unit_rate": 21.01, "valid_for": "2026-06-08" }, "meta": { "timestamp": "2026-06-09T11:38:20.037Z", "request_id": "c9db97bc-2480-491e-84a9-a4c2c3d6833c" }, "status": "ok", "message": "Currency retrieved successfully", "success": true } ``` #### `GET /v1/history` — A currency rate over recent days **Parameters:** - `code` (query, required, string) — Currency code Example: `USD` - `days` (query, optional, string) — Calendar days back (1-21, default 7) Example: `7` **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/cnb-api/v1/history?code=USD&days=7" ``` **Response:** ```json { "data": { "base": "CZK", "code": "USD", "count": 4, "source": "Česká národní banka", "history": [ { "date": "2026-06-03", "unit_rate": 20.829 }, { "date": "2026-06-04", "unit_rate": 20.81 }, { "date": "2026-06-05", "unit_rate": 20.759 }, { "date": "2026-06-08", "unit_rate": 21.01 } ] }, "meta": { "timestamp": "2026-06-09T11:38:20.388Z", "request_id": "0f4b171d-0795-4f15-bc97-6e191fedc1db" }, "status": "ok", "message": "History retrieved successfully", "success": true } ``` #### `GET /v1/rates` — CNB daily fixing (all currencies) **Parameters:** - `date` (query, optional, string) — YYYY-MM-DD for a past working day **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/cnb-api/v1/rates" ``` **Response:** ```json { "data": { "base": "CZK", "note": "rate = CZK per `amount` units of the currency; unit_rate = CZK per 1 unit", "count": 30, "rates": [ { "code": "AUD", "rate": 14.856, "amount": 1, "country": "Australia", "currency": "dollar", "unit_rate": 14.856 }, { "code": "BRL", "rate": 4.082, "amount": 1, "country": "Brazil", "currency": "real", "unit_rate": 4.082 }, { "code": "CAD", "rate": 15.079, "amount": 1, "country": "Canada", "currency": "dollar", "unit_rate": 15.079 }, { "code": "CNY", "rate": 3.098, "amount": 1, "country": "China", "currency": "renminbi", "unit_rate": 3.098 }, { "code": "DKK", "rate": 3.243, "amount": 1, "country": "Denmark", "currency": "krone", "unit_rate": 3.243 }, { "code": "EUR", "rate": 24.24, "amount": 1, "country": "EMU", "currency": "euro …(truncated, see openapi.json for full schema) ``` ### Meta #### `GET /v1/meta` — Spec **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/cnb-api/v1/meta" ``` **Response:** ```json { "data": { "source": "Česká národní banka cnbapi (live)", "service": "cnb-api", "endpoints": { "GET /v1/meta": "This document.", "GET /v1/rates": "The CNB daily fixing — all currencies vs CZK (date=YYYY-MM-DD for a past day).", "GET /v1/convert": "Convert between any two currencies via CZK (from=USD&to=EUR&amount=100&date=).", "GET /v1/history": "A currency's official rate over recent working days (code=USD&days=7).", "GET /v1/currency": "One currency's rate (code=USD, date= optional)." }, "description": "Live official Czech foreign-exchange fixing from the Czech National Bank's open API: the whole daily fixing of ~30 world currencies against the koruna (CZK), queryable for any past working day by date; one currency's rate normalised to the koruna value of a single unit; currency conversion between any two currencies crossed through the koruna, on the latest or a historical date; and a currency's official rate over recent working days. Live, no key, nothing stored. Distinct from the ECB, Fed, Bank of Canada, Norges Bank, Bank of England, Brazil and Poland central-bank APIs — this is the koruna and the CNB daily fixing, queryable by date.", "upstream_status": "ok" }, "meta": { "timestamp": "2026-06-09T11:38:20.660Z", "request_id": "4edd7740-6eaa-486f-bb3f-f8e1f7365bba" }, "status": "ok", "message": "Meta", "success": t …(truncated, see openapi.json for full schema) ``` --- Marketplace page: https://www.oanor.com/api/cnb-api OpenAPI spec: https://www.oanor.com/api/cnb-api/openapi.json