Frankfurter API
Overview
Frankfurter is an open-source currency data API backed by the European Central Bank (ECB) exchange rate dataset, providing rates for 33 major currencies updated every weekday. It supports historical queries, time series ranges, and currency conversion — all without any authentication or rate limits. The API is clean, fast, and CORS-enabled, making it a top choice for hobby and production projects alike.
Beginner Tip
No sign-up required. The live endpoint is `https://api.frankfurter.app/latest` for today's rates. To convert between currencies, add query params: `?from=USD&to=EUR`. For historical data, replace `latest` with a date like `2024-01-15`. All rates are based on the ECB daily reference rate.
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.frankfurter.app/latest?from=USD&to=EUR,JPY,GBP
- Result
- HTTP 200 · application/json · 97 bytes · compressed
- Response time
- 62 ms (median of 3) · fastest 56 ms
- Transport
- TLSv1.3 · TLS_AES_256_GCM_SHA384 · certificate issued by Google Trust Services
- Browser CORS
- Allowed — Access-Control-Allow-Origin: *
- Served by
- cloudflare
- Recorded
- 2026-08-10
Fields Returned
Top-level fields present in the response we captured, with the type and value we actually received.
| Field | Type | Value received |
|---|---|---|
| amount | integer | 1 |
| base | string | USD |
| date | string (date) | 2026-08-10 |
| rates | object | {3 fields} |
Captured Response
Captured from a real request to https://api.frankfurter.app/latest?from=USD&to=EUR,JPY,GBP on 2026-08-10. Long arrays and nested objects are truncated to keep the shape readable.
{
"amount": 1,
"base": "USD",
"date": "2026-08-10",
"rates": {
"EUR": 0.86543,
"GBP": 0.7405,
"JPY": 158.64
}
} Field Reference
amount The base amount used for conversion (default is 1). base The currency code the rates are expressed relative to. date The date of the rates in YYYY-MM-DD format (most recent ECB publishing day). rates Key-value map of currency codes to their exchange rate relative to the base currency. Implementation Example
Calls a real endpoint of this API. Replace any placeholder credentials with your own key.
const url = "https://www.frankfurter.app/docs";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data); What Can You Build?
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.
{
"status": 404,
"message": "not found"
} {
"message": "not found"
} 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.
Measured Score Breakdown
Live HTTP request to the API endpoint
Fully tested on Aug 10, 2026
Technical Specifications
Related Tags
Alternatives to Frankfurter
Technical alternatives for different use cases.
Free, open-source API backed by ECB data
Exotic currency pairs and cryptocurrency rates
European currency conversions with no API key
Open-source ECB rate API, self-hostable
Non-European currency pair coverage
Self-hosting for data sovereignty requirements
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