Frankfurter

Frankfurter is a free, open-source API for current and historical foreign exchange rates. It is based on data sets published by the European Central Bank.

No usage caps or API keys. Works great client-side in the browser or mobile apps. The public API is available at api.frankfurter.dev. If preferred, you can self-host.

Usage

Frankfurter provides endpoints to retrieve latest rates, historical data, or time series.

Latest Rates

Fetch the latest working day's rates, updated daily around 16:00 CET.

/* curl -s https://api.frankfurter.dev/v1/latest */
{
  "base": "EUR",
  "date": "2024-11-25",
  "rates": {
    "AUD": 1.6111,
    "BGN": 1.9558,
    "BRL": 6.0941,
    "CAD": 1.4648,
    "...": "..."
  }
}

Change the base currency using the base parameter. The default is EUR.

/* curl -s https://api.frankfurter.dev/v1/latest?base=USD */
{
  "base": "USD",
  "date": "2024-11-25",
  "rates": {
    "AUD": 1.5351,
    "BGN": 1.8636,
    "BRL": 5.8067,
    "CAD": 1.3957,
    "...": "..."
  }
}

Limit the response to specific target currencies.

/* curl -s https://api.frankfurter.dev/v1/latest?symbols=CHF */
{
  "base": "EUR",
  "date": "2024-11-25",
  "rates": {
    "CHF": 0.9324
  }
}

Historical Rates

Retrieve rates for a specific past date.

/* curl -s https://api.frankfurter.dev/v1/1999-01-04 */
{
  "base": "EUR",
  "date": "1999-01-04",
  "rates": {
    "AUD": 1.91,
    "CAD": 1.8004,
    "CHF": 1.6168,
    "CYP": 0.58231,
    "...": "..."
  }
}

Change the base currency and filter target currencies.

/* curl -s https://api.frankfurter.dev/v1/1999-01-04?base=USD&symbols=EUR */
{
  "base": "USD",
  "date": "1999-01-04",
  "rates": {
    "EUR": 0.84825
  }
}

Time Series Data

Fetch rates over a period.

/* curl -s https://api.frankfurter.dev/v1/2000-01-01..2000-12-31 */
{
  "base": "EUR",
  "start_date": "1999-12-30",
  "end_date": "2000-12-29",
  "rates": {
    "1999-12-30": {
      "AUD": 1.5422,
      "CAD": 1.4608,
      "CHF": 1.6051,
      "CYP": 0.57667,
      "...": "..."
    },
    "2000-01-03": {
      "AUD": 1.5346,
      "CAD": 1.4577,
      "CHF": 1.6043,
      "CYP": 0.5767,
      "...": "..."
    },
    "2000-01-04": {
      "AUD": 1.5677,
      "CAD": 1.4936,
      "CHF": 1.6053,
      "CYP": 0.5775,
      "...": "..."
    },
    "2000-01-05": {
      "AUD": 1.5773,
      "CAD": 1.5065,
      "CHF": 1.606,
      "CYP": 0.5778,
      "...": "..."
    },
    "...": "..."
  }
}

Fetch rates up to the present.

/* curl -s https://api.frankfurter.dev/v1/2024-01-01.. */
{
  "base": "EUR",
  "start_date": "2023-12-29",
  "end_date": "2024-11-25",
  "rates": {
    "2023-12-29": {
      "AUD": 1.6263,
      "BGN": 1.9558,
      "BRL": 5.3618,
      "CAD": 1.4642,
      "...": "..."
    },
    "2024-01-02": {
      "AUD": 1.6147,
      "BGN": 1.9558,
      "BRL": 5.3562,
      "CAD": 1.4565,
      "...": "..."
    },
    "2024-01-03": {
      "AUD": 1.6236,
      "BGN": 1.9558,
      "BRL": 5.3859,
      "CAD": 1.4574,
      "...": "..."
    },
    "2024-01-04": {
      "AUD": 1.628,
      "BGN": 1.9558,
      "BRL": 5.3761,
      "CAD": 1.4603,
      "...": "..."
    },
    "...": "..."
  }
}

Tip: Filter currencies to reduce response size and improve performance.

/* curl -s https://api.frankfurter.dev/v1/2024-01-01..?symbols=USD */
{
  "base": "EUR",
  "start_date": "2023-12-29",
  "end_date": "2024-11-25",
  "rates": {
    "2023-12-29": {
      "USD": 1.105
    },
    "2024-01-02": {
      "USD": 1.0956
    },
    "2024-01-03": {
      "USD": 1.0919
    },
    "2024-01-04": {
      "USD": 1.0953
    },
    "...": "..."
  }
}

Available currencies

Get supported currency symbols and their full names.

/* curl -s https://api.frankfurter.dev/v1/currencies */
{
  "AUD": "Australian Dollar",
  "BGN": "Bulgarian Lev",
  "BRL": "Brazilian Real",
  "CAD": "Canadian Dollar",
  "...": "..."
}

Currency Conversion

Perform currency conversion by fetching the exchange rate and calculating in your code.

function convert(from, to, amount) {
  fetch(`https://api.frankfurter.dev/v1/latest?base=${from}&symbols=${to}`)
    .then((resp) => resp.json())
    .then((data) => {
      const convertedAmount = (amount * data.rates[to]).toFixed(2);
      alert(`${amount} ${from} = ${convertedAmount} ${to}`);
    });
  }

convert("EUR", "USD", 10);

Click or tap to execute the code.

Deployment

If you prefer not to use our hosted service, you can self-host with Docker.

# Runs frankfurter on port 8080
docker run -d -p 8080:8080 \
  --pull always \
  lineofflight/frankfurter

Quick answers

Is the API free for commercial use?

Yes, absolutely.

Does the API have any call limits?

There are no limits. However, for high-volume queries, it’s more efficient to query the European Central Bank data directly from your server than using our API.

Will the API work in the future?

We've been running for over a decade and have no plans to shut down. For critical applications, we recommend self-hosting for greater control.