Frankfurter

Overview

Frankfurter is a widely used free API for accessing current and historical foreign exchange rates. Established in 2011, it focuses on providing straightforward currency conversion data without the requirement of an API key for basic usage, simplifying the integration process for developers. The service sources its exchange rates from the European Central Bank (ECB), which provides daily reference rates for the euro against 45 major world currencies. This makes Frankfurter particularly useful for applications requiring data anchored to European economic standards.

The API is designed for ease of use, making it an option for projects that need quick integrations, such as internal tools, educational applications, or prototypes. It provides daily updated exchange rates and supports retrieval of historical data for up to one year, covering all currencies tracked by the ECB. This scope is suitable for a range of use cases from simple currency conversion widgets to historical analysis tools. While it offers a comprehensive set of major currencies, developers should note that its data is updated daily, not in real-time, which differentiates it from services that offer minute-by-minute or intraday updates. For such requirements, alternative providers like Fixer's real-time API might be more appropriate.

Frankfurter's design philosophy prioritizes simplicity and accessibility. Its architecture ensures that developers can retrieve exchange rates with minimal setup, making it a common choice for those exploring fintech integrations or building applications where high-frequency data updates are not critical. The API endpoint structure is intuitive, allowing requests for specific dates, base currencies, and target currencies. This flexibility supports various query patterns, from fetching the latest rates to retrieving rates on a particular historical date. Its developer experience is often cited as a key advantage, especially for projects with budget constraints or those requiring rapid deployment.

The service is particularly well-suited for applications that perform simple currency conversions, display historical trends over a limited period, or require a reliable, free source of exchange rate data. It is not designed for high-volume financial trading platforms or applications demanding sub-second updates, where latency and data freshness are paramount. However, for a broad spectrum of general-purpose applications, Frankfurter provides a stable and easy-to-implement solution for currency exchange rate data.

Key features

• Free and Open-Source: Offers full functionality without any subscription fees or API keys for basic access, promoting accessibility for developers (Frankfurter documentation).
• Daily Exchange Rate Updates: Provides exchange rates that are updated daily, reflecting the latest reference rates from the European Central Bank.
• Comprehensive Currency Support: Covers 45 major world currencies, allowing conversions and data retrieval for a wide range of global currencies.
• Historical Data Access: Enables developers to retrieve historical exchange rate data for up to one year, facilitating trend analysis and back-dated calculations.
• Simple HTTP API: Features an easy-to-understand RESTful API with clear endpoints for fetching current, latest, and historical rates.
• No API Key Required: Simplifies integration by removing the need for authentication for standard usage, reducing setup time.
• JSON Response Format: Returns data in a standard JSON format, which is easily parsable across various programming languages and environments.

Pricing

As of May 2026, Frankfurter operates under a completely free model, providing its core services without any charges or tiered plans.

For detailed information on usage and terms, refer to the Frankfurter documentation.

Common integrations

Frankfurter's straightforward API design facilitates integration into various applications and systems. Due to its RESTful nature and JSON output, it can be consumed by virtually any programming language or platform capable of making HTTP requests. Common integration scenarios include:

• Web Applications: Integrating into frontend (e.g., React, Vue, Angular) or backend (e.g., Node.js, Python/Django, Ruby on Rails) web applications for displaying currency conversion tools or historical rate charts.
• Mobile Applications: Providing currency conversion functionality within iOS or Android apps for travelers or financial tracking.
• Spreadsheet Automation: Using tools like Google Apps Script or VBA to fetch and update currency rates directly within spreadsheets for financial modeling or reporting.
• Internal Tools and Dashboards: Building custom dashboards or internal tools for businesses to monitor exchange rate fluctuations relevant to international operations.
• IoT Devices: Incorporating currency exchange information into smart displays or other IoT devices that require external data feeds.
• Educational Projects: Serving as a data source for coding bootcamps, university projects, or personal learning initiatives due to its ease of use and free access.

Alternatives

• ExchangeRate-API: Offers free and paid tiers with daily and hourly updates, covering 160+ currencies with a focus on ease of integration.
• Fixer: Provides real-time and historical exchange rates for 170 world currencies, with a focus on reliability and high-frequency updates for professional use cases.
• Open Exchange Rates: Delivers real-time exchange rates with a free tier and extensive historical data, sourced from multiple providers.

Getting started

To get started with Frankfurter, you can make a simple HTTP GET request to its API endpoints. The API does not require an API key for basic usage. Below is an example using Python to fetch the latest exchange rates with EUR as the base currency.

import requests

def get_latest_exchange_rates(base_currency='EUR'):
    url = f"https://api.frankfurter.app/latest?from={base_currency}"
    try:
        response = requests.get(url)
        response.raise_for_status() # Raise an HTTPError for bad responses (4xx or 5xx)
        data = response.json()
        if 'rates' in data:
            print(f"Latest exchange rates from {data['base']} on {data['date']}:")
            for currency, rate in data['rates'].items():
                print(f"  1 {data['base']} = {rate} {currency}")
            return data['rates']
        else:
            print("Error: 'rates' key not found in response.")
            return None
    except requests.exceptions.HTTPError as http_err:
        print(f"HTTP error occurred: {http_err}")
        return None
    except requests.exceptions.RequestException as req_err:
        print(f"Request error occurred: {req_err}")
        return None

# Example usage:
if __name__ == "__main__":
    rates = get_latest_exchange_rates('USD')
    if rates:
        print("\n--- Fetching historical rate for a specific date ---")
        # Example to get rates for a specific date (e.g., 2023-01-01)
        historical_url = "https://api.frankfurter.app/2023-01-01?from=USD&to=GBP"
        try:
            historical_response = requests.get(historical_url)
            historical_response.raise_for_status()
            historical_data = historical_response.json()
            if 'rates' in historical_data and 'GBP' in historical_data['rates']:
                print(f"On {historical_data['date']}, 1 {historical_data['base']} = {historical_data['rates']['GBP']} GBP")
            else:
                print("Could not retrieve historical rate for GBP.")
        except requests.exceptions.RequestException as e:
            print(f"Error fetching historical data: {e}")

This Python script defines a function get_latest_exchange_rates that fetches the most recent exchange rates using the Frankfurter API. It handles potential HTTP and request errors. The example then demonstrates how to call this function and also how to retrieve a specific historical rate. For more detailed API endpoints and request parameters, consult the Frankfurter API documentation.