| name | currency |
| description | Currency exchange rates and conversion via the Frankfurter API (no key). Use for FX rates, "convert X to Y", or historical/time-series rates. |
| version | 1.0.0 |
| requires_tools | ["os.http.request","os.shell.run"] |
| dangerous | false |
currency
Fetch exchange rates and convert money amounts through the free, key-less
Frankfurter API (ECB-sourced fiat rates, updated
daily ~16:00 CET). Prefer os.http.request GET; if the host allowlist is
not null, it must include api.frankfurter.dev.
Fiat only — no crypto, no precious metals on v1. Rates refresh on business days,
so weekend/holiday requests return the most recent business-day rate.
Endpoints (v1, stable)
Base URL: https://api.frankfurter.dev/v1
| Goal | URL |
|---|
| Latest, EUR base, all currencies | /latest |
| Latest with base + targets | /latest?base=USD&symbols=EUR,GBP |
| Convert an amount | /latest?base=USD&symbols=EUR&amount=100 |
| Historical (single day) | /2024-01-15?base=USD&symbols=EUR |
| Time series (date range) | /2024-01-01..2024-01-31?base=USD&symbols=EUR |
| Supported currencies | /currencies |
symbols is a comma-separated list of ISO 4217 codes. amount multiplies the
returned rate, so amount=100&base=USD&symbols=EUR gives "100 USD in EUR".
Calling convention
Latest rate with os.http.request:
[{ "tool": "os.http.request", "args": { "method": "GET", "url": "https://api.frankfurter.dev/v1/latest?base=USD&symbols=EUR,GBP" } }]
Convert 250 USD to JPY:
[{ "tool": "os.http.request", "args": { "method": "GET", "url": "https://api.frankfurter.dev/v1/latest?base=USD&symbols=JPY&amount=250" } }]
Fallback if os.http.request is unavailable or the host is not allowlisted:
[{ "tool": "os.shell.run", "args": { "cmd": "curl", "args": ["-fsS", "--max-time", "25", "https://api.frankfurter.dev/v1/latest?base=USD&symbols=EUR&amount=100"] } }]
Response shape
{ "amount": 100.0, "base": "USD", "date": "2026-05-29", "rates": { "EUR": 92.13 } }
rates[<symbol>] already reflects amount. Always report the date so the user
knows how fresh the quote is.
When to use
- "What's the USD/EUR rate?", "convert 50 GBP to PLN", "rate of X in Y".
- Historical FX on a given date, or a rate trend over a period.
When NOT to use
- Crypto prices (BTC, ETH) — Frankfurter is fiat-only.
- Real-time / intraday tick data — rates are daily reference rates.
- Precious metals (XAU, XAG) — not available on v1.
Rules
- Echo the
date field with every quote; rates are daily, not live.
- Validate currency codes against
/currencies if the user gives an unusual code.
- For "convert N", pass
amount=N rather than multiplying client-side — the API
keeps full precision.
- Unknown currency codes return HTTP 404 / 422; surface a clear "unsupported
currency" message instead of the raw error.
