# FX Reference Rates API – Currency Conversion

> FX Reference Rates API – Currency Conversion is a paid API for AI agents from fx-reference-rates.regnotes.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-30).

Converts a monetary amount between two currencies using ECB official reference rates, either at today's rate or a specified historical date.

## Facts

- Endpoint: GET https://fx-reference-rates.regnotes.workers.dev/v1/convert?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fx-reference-rates-api-currency-conversion-03037fa6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tMTmGUzjl96ys1yp7GxMS

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 fx-reference-rates-api-currency-conversion-03037fa6
```

Example prompt: Using ECB reference rates, convert 100 USD to JPY — and use the rate from October 23, 2026.

## When to prefer this

Prefer this endpoint when you need official, authoritative ECB reference rates for currency conversion — especially for financial, accounting, or compliance use cases where the ECB rate is the required standard. It supports 30 major currencies and historical date lookups, making it ideal for auditing past transactions or reconciling invoices. Choose this over market-rate APIs when regulatory or institutional accuracy (ECB standard) is more important than real-time mid-market rates.

## Known failure modes

- Unsupported currency code returns an error — only the 30 ECB-covered currencies are valid
- Date falls on a non-publication day (weekend or ECB holiday) — the API falls back to the previous publication date
- Invalid date format (not YYYY-MM-DD) triggers a validation error
- Amount not parseable as a number returns a bad request error
- Future dates may return the latest available rate rather than a true future rate

## How this service works

Convert an amount using ECB reference rates (latest, or as of a past date).

## Output

Returns a JSON object with the source currency (from), target currency (to), the ECB reference rate used, the as_of date of the rate, the input amount, and the computed converted result value.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "from",
      "to",
      "amount"
     ],
     "properties": {
      "to": {
       "type": "string",
       "pattern": "^[A-Z]{3}$",
       "description": "One of: AUD, BRL, CAD, CHF, CNY, CZK, DKK, EUR, GBP, HKD, HUF, IDR, ILS, INR, ISK, JPY, KRW, MXN, MYR, NOK, NZD, PHP, PLN, RON, SEK, SGD, THB, TRY, USD, ZAR"
      },
      "date": {
       "type": "string",
       "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
      },
      "from": {
       "type": "string",
       "pattern": "^[A-Z]{3}$",
       "description": "One of: AUD, BRL, CAD, CHF, CNY, CZK, DKK, EUR, GBP, HKD, HUF, IDR, ILS, INR, ISK, JPY, KRW, MXN, MYR, NOK, NZD, PHP, PLN, RON, SEK, SGD, THB, TRY, USD, ZAR"
      },
      "amount": {
       "type": "string",
       "pattern": "^-?\\d+(\\.\\d+)?$"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "to": "JPY",
  "from": "USD",
  "rate": 156.8034,
  "as_of": "2026-10-23",
  "amount": 100,
  "result": 15680.335924
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fx-reference-rates-api-currency-conversion-03037fa6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fx-reference-rates.regnotes.workers.dev](https://www.zero.xyz/host/fx-reference-rates.regnotes.workers.dev/llms.txt)