# offercheck FX Currency Converter

> offercheck FX Currency Converter is a paid API for AI agents from offercheck.offercheck.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).

Converts currency amounts using ECB reference rates, supporting historical dates and multiple target currencies in one call

## Facts

- Endpoint: GET https://offercheck.offercheck.workers.dev/v1/fx?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/offercheck-fx-currency-converter-8795543e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vjcDLiGjjHeOLpJlM83HB

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 offercheck-fx-currency-converter-8795543e
```

Example prompt: What's the current ECB exchange rate for 250 USD to EUR and GBP? I need the official reference rate, not a broker rate.

## When to prefer this

Choose this endpoint when you need official ECB reference rates rather than live market/broker rates — ideal for accounting, compliance, invoicing, or any use case requiring an authoritative published rate. It supports historical lookups back to 1999 and multi-currency batch conversion in a single call, making it more efficient than looping individual conversions. Prefer alternatives if you need real-time tick-level FX rates or currencies outside the ECB's 30-currency basket.

## Known failure modes

- Unsupported currency code returns an error — only the 30 ECB-published currencies are available
- Requested historical date falls on a non-ECB business day (weekends, holidays) — nearest available date may be returned or an error issued
- Date before 1999-01-04 (ECB history start) is out of range
- Malformed date format (not YYYY-MM-DD) causes a validation error
- Non-EUR cross-rate pairs are computed through EUR, so rounding may slightly differ from direct market rates

## How this service works

Convert between 30 major currencies (USD, EUR, GBP, JPY, CHF, CNY, INR, ILS, AUD, CAD, ...) using the European Central Bank's daily reference rates: rate and converted amount for one or many target currencies, optional historical date back to 1999. Returns the ECB rate date and source. $0.002 per call.

## Output

A JSON object containing the conversion date, base currency, amount, and a rates map where each target currency key holds both the raw exchange rate and the converted amount. Also includes the data source attribution (ECB via frankfurter.dev), a fetched_at timestamp, any warnings, and response latency in milliseconds.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "to": {
       "type": "string",
       "default": "EUR",
       "description": "Target currency or comma-separated list (default EUR); any of the 30 ECB currencies"
      },
      "date": {
       "type": "string",
       "description": "Optional historical date YYYY-MM-DD (ECB business days from 1999-01-04); omit for the latest rates"
      },
      "from": {
       "type": "string",
       "default": "USD",
       "description": "Base currency, ISO 4217 code (default USD)"
      },
      "amount": {
       "type": "string",
       "default": "1",
       "pattern": "^[0-9]+(\\.[0-9]+)?$",
       "description": "Amount in the base currency to convert, as a decimal number string, e.g. \"100\" (default 1). Query parameters are strings, so the Coinbase Bazaar validator rejects a numeric type here."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ms": 95,
  "date": "2026-09-25",
  "from": "USD",
  "rates": {
   "EUR": {
    "rate": 0.87696,
    "converted": 87.696
   },
   "GBP": {
    "rate": 0.75458,
    "converted": 75.458
   }
  },
  "amount": 100,
  "source": "European Central Bank euro foreign exchange reference rates (published once per business day ~16:00 CET) via frankfurter.dev; non-EUR pairs are cross rates through EUR",
  "warnings": [],
  "fetched_at": "2026-09-25T20:00:00.000Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/offercheck-fx-currency-converter-8795543e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from offercheck.offercheck.workers.dev](https://www.zero.xyz/host/offercheck.offercheck.workers.dev/llms.txt)