Guide

Komerční banka Exchange Rate API: CZK Buy and Sell Rates as JSON

By Madhushan November 13, 2026 6 min read

Reviewed by Madhushan, Fintech Developer — November 2026

Komerční banka is one of the three largest banks in Czechia and part of the Société Générale group. Its exchange-rate list gives cash and non-cash buy and sell rates for about 16 currencies, with the Czech National Bank’s rate alongside and the time the list became valid. This guide shows how to read that board as JSON: what the rates mean, how they compare with the Czech National Bank official rate, and the calls that return them.

What the KB board shows

16 currencies against the Czech koruna: AUD, CAD, CHF, CNY, DKK, EUR, GBP, HUF, JPY, NOK, PLN, RON, RUB, SEK, TRY and USD. Every value is CZK per 1 unit of the foreign currency.
The non-cash (transfer) buy / sell pair. Czech banks publish two boards: valuty (cash, over the counter) and devizy (non-cash, used for transfers and card or account conversions). The pair here is the non-cash board. The Czech National Bank sets one official rate each business day, which accounting and tax rules refer to.
USD on 13 November 2026: KB bought at 21.1728 and sold at 22.8912 CZK, a spread of 7.80%. The Czech National Bank official rate was 22.014, so the bank's mid sat +0.08% from it.
The bank's own timestamp. The page prints a last-updated stamp (2026-11-13 07:00:00 (Prague) on the board above), returned as bank_updated_at next to our captured_at.
Every day's board is kept permanently, from 13 November 2026, the day collection started. Read one past day with ?date=, or a range for one currency with the /history endpoint (paid plans).

Spreads across the board

On the 13 November 2026 board the tightest spreads were DKK (7.80%), HUF (7.80%), AUD (7.80%) and the widest TRY (19.50%), RUB (15.30%), CNY (12.40%). Spread is (sell − buy) ÷ mid: what a round trip through the bank costs, before any fees. The API returns it on every row as spread_pct, so you can rank currencies or alert when a bank widens its board.

Get the board (REST)

You need an API key; the free key works. The full board:

curl "https://allratestoday.com/api/v1/bank-rates/cz/komercni" \
  -H "Authorization: Bearer art_live_your_key"

What comes back (the 13 November 2026 board, first three rows):

{
  "bank": "komercni",
  "name": "Komerční banka",
  "country": "cz",
  "quote_ccy": "CZK",
  "bank_updated_at": "2026-11-13 07:00:00 (Prague)",
  "basis": "Non-cash (transfer) buy / sell",
  "captured_at": "2026-11-13T13:36:04.804Z",
  "rates": [
    {"ccy":"AUD","buy":14.4169,"sell":15.5871,"mid":15.002,"spread_pct":7.8,"official":15.011,"vs_official_pct":-0.06},
    {"ccy":"CAD","buy":14.842,"sell":16.0466,"mid":15.4443,"spread_pct":7.8,"official":15.451,"vs_official_pct":-0.043},
    {"ccy":"CHF","buy":25.3779,"sell":27.4377,"mid":26.4078,"spread_pct":7.8,"official":26.423,"vs_official_pct":-0.058},
    … 13 more currencies
  ],
  "disclaimer": "…",
  "attribution": { … }
}

One currency, with the row fields at the top level:

curl "https://allratestoday.com/api/v1/bank-rates/cz/komercni?ccy=USD" \
  -H "Authorization: Bearer art_live_your_key"

{
  "bank": "komercni",
  "name": "Komerční banka",
  "country": "cz",
  "quote_ccy": "CZK",
  "bank_updated_at": "2026-11-13 07:00:00 (Prague)",
  "basis": "Non-cash (transfer) buy / sell",
  "captured_at": "2026-11-13T13:36:04.804Z",
  "ccy": "USD",
  "buy": 21.1728,
  "sell": 22.8912,
  "mid": 22.032,
  "spread_pct": 7.8,
  "official": 22.014,
  "vs_official_pct": 0.082,
  "disclaimer": "Retail buy/sell rates as displayed on each bank’s own website at capture time, quoted as home currency per 1 unit of foreign currency. Indicative only: banks change these through the day, apply them at the counter or in-app, and they are not official or reference rates. For the rate a regulation names, use the central-bank endpoints.",
  "attribution": {
    "source": "Board rates published by Komerční banka on its own website, collected by AllRatesToday",
    "bank_url": "https://www.kb.cz/en/exchange-rates",
    "url": "https://allratestoday.com/bank-exchange-rate-api/cz/komercni/",
    "terms": "Public pages that show the rates need a visible link to allratestoday.com"
  }
}

The board as it stood on a past day:

curl "https://allratestoday.com/api/v1/bank-rates/cz/komercni?date=2026-11-13" \
  -H "Authorization: Bearer art_live_your_key"

One currency over a date range, one row per day (paid plans; add &format=csv, xml or xlsx for a file):

curl "https://allratestoday.com/api/v1/bank-rates/cz/komercni/history?ccy=USD&from=2026-11-13&to=2026-11-13" \
  -H "Authorization: Bearer art_live_your_key"

JavaScript

npm install @allratestoday/sdk

import { AllRatesToday } from '@allratestoday/sdk';

const client = new AllRatesToday({ apiKey: 'art_live_your_key' });

// Komerční banka's USD row
const r = await client.bankRates('cz', { bank: 'komercni', ccy: 'USD' });
console.log(`KB buys USD at ${r.buy}, sells at ${r.sell} CZK`);

// The board as it stood on a past day
const past = await client.bankRates('cz', { bank: 'komercni', date: '2026-11-13' });
console.log(past.snapshot_date, past.rates.length);

Python

import requests

r = requests.get(
    "https://allratestoday.com/api/v1/bank-rates/cz/komercni",
    headers={"Authorization": "Bearer art_live_your_key"},
    timeout=10,
)
r.raise_for_status()
for row in r.json()["rates"]:
    print(row["ccy"], row["buy"], row["sell"], row["spread_pct"])

Board rate or official rate?

The Czech National Bank rate is the one tax, accounting and customs rules in Czechia name; nobody transacts at it. KB's board is the price a customer actually gets. The API puts both on every row: official is the central bank's rate for the same currency and vs_official_pct is how far the bank's mid sits from it. Use the board to show customers a real price, compare banks for a remittance, or keep a dated record of what the bank quoted; use the Czech National Bank endpoint when a rule asks for the official rate.

FAQ

Where do the Komerční banka rates come from?

From the bank's own public rates page (https://www.kb.cz/en/exchange-rates), read hourly. AllRatesToday does not change the numbers: each row is the buy and sell price KB shows, with the mid, the spread and the Czech National Bank rate added.

Are these the official CZK exchange rates?

No. They are KB's retail prices for customers. The official rate in Czechia is the Czech National Bank rate, which the API returns as official on each row where the central bank has one, and in full from the central-bank endpoint.

How often is the KB board updated?

AllRatesToday reads the page every hour. The bank's own last-updated stamp is returned as bank_updated_at, so you can tell a fresh read of an unchanged board from a new board.

Can I get KB rates for a past date?

Yes, from 13 November 2026 onward; every day's board is kept permanently. Add ?date=YYYY-MM-DD for one day: the response is the board captured that day, or the nearest earlier day within five days, with date_requested and snapshot_date added. For a range, /history?ccy=USD&from=…&to=… returns one row per day as JSON, CSV, XML or XLSX on paid plans.

Do I need an API key?

Yes. Commercial bank boards need an API key; any plan works, the free key included, and each call counts against the plan. Public pages or widgets that show the rates need a visible link to allratestoday.com.

Komerční banka rates, as JSON

Free API key, hourly board captures, the official rate alongside.

Get your free API key