National Bank of Poland API

Overview

Measurement Record

What actually happened when we called this API from our own infrastructure. Every value below was recorded by the request, not copied from the provider's documentation.

Request

GET https://api.nbp.pl/api/exchangerates/tables/A/?format=json

Result

HTTP 200 · application/json · 1,955 bytes · compressed

Response time

277 ms (median of 3) · fastest 273 ms

Transport

TLSv1.3 · TLS_AES_256_GCM_SHA384 · certificate issued by Asseco Data Systems S.A.

Browser CORS

Allowed — Access-Control-Allow-Origin: *

Recorded

2026-08-10

Fields Returned

Top-level fields present in the response we captured, with the type and value we actually received.

Captured Response

Captured from a real request to https://api.nbp.pl/api/exchangerates/tables/A/?format=json on 2026-08-10. Long arrays and nested objects are truncated to keep the shape readable.

[
  {
    "table": "A",
    "no": "153/A/NBP/2026",
    "effectiveDate": "2026-08-10",
    "rates": [
      {
        "…": "(3 more fields)"
      }
    ]
  }
]

Implementation Example

Calls a real endpoint of this API. Replace any placeholder credentials with your own key.

const url = "http://api.nbp.pl/";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

import requests

url = "http://api.nbp.pl/"
headers = {}

response = requests.get(url, headers=headers, timeout=30)
response.raise_for_status()
data = response.json()
print(data)

curl -H "Accept: application/json" "https://api.nbp.pl/api/exchangerates/tables/A/?format=json"

What Can You Build?

// Convert USD to EUR
const response = await fetch(`http://api.nbp.pl/en.html`);
const data = await response.json();
const rate = data.rates?.EUR || data.conversion_rate || data.EUR;
const amount = 100;
const converted = (amount * rate).toFixed(2);
console.log(`$${amount} USD = €${converted} EUR (rate: ${rate})`);

// Multi-currency conversion widget
const response = await fetch(`http://api.nbp.pl/en.html`);
const data = await response.json();
const rates = data.rates || data;
const currencies = ['EUR', 'GBP', 'JPY', 'CAD'];
const usdAmount = 100;
currencies.forEach(cur => {
  const rate = rates[cur] || 0;
  console.log(`$${usdAmount} = ${(usdAmount * rate).toFixed(2)} ${cur}`);
});

// Fetch historical exchange rates
const response = await fetch(`http://api.nbp.pl/en.html`);
const data = await response.json();
const rates = data.rates || data;
console.log('Exchange rates:', rates);
const pairs = Object.entries(rates).slice(0, 5);
pairs.forEach(([currency, rate]) => {
  console.log(`1 USD = ${rate} ${currency}`);
});

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

How This API Fails

We deliberately sent this API a broken request and recorded exactly what came back on 2026-08-10. Knowing the shape of an error before you hit it makes error handling much easier to write.

404 NotFound

Common Errors & Troubleshooting

Generated guidance based on this API's documentation, not observed by us. Treat it as a starting point and check against the provider's own error reference.