# ArgonautWorks ECB FX Reference API

> ArgonautWorks ECB FX Reference API is a paid API for AI agents from official-fx-reference.vercel.app, paid per call via x402, $0.0015/call, status unknown (last checked 2026-09-15).

Converts a currency amount between two currencies using ECB official reference rates with explicit cross-rate calculation and source citation

## Facts

- Endpoint: GET https://official-fx-reference.vercel.app/api/v1/convert
- Price: $0.0015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/argonautworks-ecb-fx-reference-api-ad903327
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_c-2kDF6xijoq1JfwgkM1j

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 argonautworks-ecb-fx-reference-api-ad903327
```

Example prompt: Using ECB official reference rates, convert 250 US dollars to Japanese yen and show me the cross-rate calculation and the source publication date.

## When to prefer this

Choose this endpoint when you need auditable, source-cited FX conversions backed by ECB official reference rates with explicit cross-rate math shown — ideal for compliance, reporting, or financial workflows requiring a verifiable, non-commercial rate source. Prefer this over generic FX APIs when transparency of calculation methodology and provenance matter, or when you need the ECB specifically as the authoritative source. Not suitable for live market trading rates or real-time bid/ask spreads.

## Known failure modes

- Unsupported or unrecognized 3-letter currency code returns an error — ECB only publishes rates for a limited set of currencies
- Amount of zero or negative value rejected due to exclusiveMinimum constraint
- Amount exceeding 999,999,999 rejected by schema maximum
- Stale cache may return rates from prior business day if ECB has not yet published for the current date
- ECB does not publish rates on weekends or holidays, so latest available date may lag
- Network or upstream ECB feed unavailability could cause service errors

## How this service works

Source-cited ECB foreign-exchange reference conversion with explicit cross-rate math. Underlying ECB statistics are available free; the fee covers validation, calculation, and machine-ready delivery.

## Output

Returns a JSON object with the converted amount, the ECB reference rate for the currency pair, the individual rates per EUR used in cross-rate math, the publication date and observation timestamp, a direct source URL to the ECB dataset, cache freshness metadata, and a disclaimer about the informational nature of ECB rates.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "base": {
       "type": "string",
       "default": "USD",
       "pattern": "^[A-Za-z]{3}$",
       "description": "Three-letter source currency code. Defaults to USD."
      },
      "quote": {
       "type": "string",
       "default": "EUR",
       "pattern": "^[A-Za-z]{3}$",
       "description": "Three-letter destination currency code. Defaults to EUR."
      },
      "amount": {
       "type": "number",
       "default": 1,
       "maximum": 999999999,
       "exclusiveMinimum": 0
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "base": "USD",
  "cache": {
   "stale": false,
   "age_ms": 0
  },
  "quote": "JPY",
  "source": {
   "url": "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml",
   "dataset": "Euro foreign exchange reference rates",
   "provider": "European Central Bank",
   "available_free": true
  },
  "disclaimer": "ECB reference rates are informational averages and may not reflect rates available for market transactions. This service is independent of and not endorsed by the ECB.",
  "calculation": "quote_per_eur / base_per_eur; the cross-rate and converted amount are derived values",
  "observed_at": "2026-08-04T21:30:00.000Z",
  "input_amount": 100,
  "published_date": "2026-08-04",
  "reference_rate": 154.325,
  "converted_amount": 15432.5,
  "underlying_data_notice": "The underlying ECB reference-rate statistics are available free of charge from the European Central Bank; this paid API charges for validation, cross-rate calculation, and machine-ready delivery.",
  "reference_rates_per_eur": {
   "JPY": 177.47375,
   "USD": 1.15
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/argonautworks-ecb-fx-reference-api-ad903327/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from official-fx-reference.vercel.app](https://www.zero.xyz/host/official-fx-reference.vercel.app/llms.txt)