# ECB Foreign Exchange Rate API (Frankfurter)

> ECB Foreign Exchange Rate API (Frankfurter) is a paid API for AI agents from gateway.stride20k.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-15).

Returns the official ECB daily reference exchange rate for any supported fiat currency pair, sourced from the Frankfurter API.

## Facts

- Endpoint: GET https://gateway.stride20k.com/fx/:base/:quote
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ecb-foreign-exchange-rate-api-frankfurter-6e12d889
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_b9AB9uvM9Ku-UhhsipD87

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability ecb-foreign-exchange-rate-api-frankfurter-6e12d889
```

Example prompt: What's the official ECB reference rate for USD to EUR today? I need it to normalize our revenue figures for financial reporting.

## When to prefer this

Choose this endpoint when you need an authoritative, official daily reference rate suitable for financial reporting, settlement, accounting normalization, or pricing standardization across ~30 major currencies. Prefer this over scraped or broker rates when regulatory or audit-grade provenance matters. Not suitable for live trading, real-time arbitrage, or intraday rate tracking since rates update only once per business day.

## Known failure modes

- Unsupported currency code (e.g. exotic or non-ECB currency) returns an error — only ~30 major ISO 4217 currencies are supported
- Weekend or holiday request may return the most recent prior business day's rate since ECB publishes once per business day around 16:00 CET
- Malformed 3-letter currency code (e.g. wrong length or non-alpha characters) rejected by path parameter validation
- Rate not yet published for current day if requested before ~16:00 CET — previous business day's rate returned
- Upstream Frankfurter API or ECB outage may cause upstream fetch failure

## How this service works

Foreign exchange rate API: official ECB reference rate for any fiat currency pair (USD/EUR, GBP/JPY — ~30 major ISO 4217 currencies) via the open-source Frankfurter API. Published once per business day around 16:00 CET — a daily reference rate for settlement and normalization, not a live trading feed. Use for currency conversion, pricing normalization, and financial reporting by agents. Cached up to 1 hour.

## Output

Returns a JSON object containing the exchange rate (units of quote currency per 1 unit of base currency), the ECB publication date (YYYY-MM-DD), both currency codes, and metadata indicating whether the response was cached, the upstream source (frankfurter/ECB), and the fetch timestamp.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ecb-foreign-exchange-rate-api-frankfurter-6e12d889/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gateway.stride20k.com](https://www.zero.xyz/host/gateway.stride20k.com/llms.txt)