# x402 Checker FX Currency Converter

> x402 Checker FX Currency Converter is a paid API for AI agents from x402-checker.nock-for-mak.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Converts a specified amount from one ISO-4217 currency to one or more target currencies using ECB reference rates via Frankfurter

## Facts

- Endpoint: GET https://x402-checker.nock-for-mak.workers.dev/fx
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-checker-fx-currency-converter-c47abbb3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PqVfT5KuqeUaKGJmWKuuw

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 x402-checker-fx-currency-converter-c47abbb3
```

Example prompt: Convert 250 USD to EUR and GBP using today's ECB reference rates.

## When to prefer this

Choose this endpoint when you need real-time ECB-sourced foreign exchange rates for one or more ISO-4217 currency pairs, especially when you need to convert a specific amount and want both the rate and the converted value in a single call. It supports up to 12 target currencies simultaneously, making it efficient for multi-currency conversion needs.

## Known failure modes

- Invalid or unsupported ISO-4217 currency code returns an error
- More than 12 target currencies requested exceeds the maximum
- Missing required 'from' or 'to' query parameter returns a 400-level error
- Frankfurter upstream outage may cause delayed or failed rate retrieval
- Payment of $0.01 USDC not completed results in 402 Payment Required

## How this service works

Free x402 wash/honesty look, free GET /board pay-to-rank, free GET /name?n= ENS-style agent name lookup, $0.05 USDC POST /name (30 day TTL) and POST /bid (adds to 24h total) and /report, $0.01 USDC POST /check/batch (max 10 URLs), /who, /md, /headers, /json, /sanctions, /domain, /ssl, /ens, /redirect, /gas, /price, /tx, /block, /token, /sig, /pm, /fng, /tsec, /dex, /now, /find, /geo, /fx, /wx, /quote, /hn, /arxiv, /so, /cve, /gh, /wiki, /email, /bizdays, and /tz, and /cron, and /crypto-news on Base. GET /check stays free for one URL. Streamable-HTTP MCP at POST /mcp (initialize + tools/list free; tools board and name_lookup free, bid and name_register $0.05). Crawler files: GET /llms.txt and GET /.well-known/agent.json (also agent-card.json). /headers is a raw header dump. /json validates JSON against a JSON Schema. /sanctions is an OFAC SDN digital-currency screen. /domain is a DNS/RDAP/TLS dossier. /ssl is TLS cert facts from public CT plus a live HTTPS HEAD. /ens is an ENS/Basename resolver (public HTTP; not this origin's POST /name registrar). /redirect is a Location-header redirect chain / URL unwrap (public http(s), SSRF-safe). /gas is a Base gas oracle (public RPC: gasPrice, maxPriorityFee, feeHistory). /price is a spot USD oracle (public DeFiLlama; ETH/USDC/BTC default; optional Base token=0x). /tx is a Base transaction + receipt lookup (public RPC; hash required; unknown hash is paid 200 with found:false). /block is a Base block header lookup (public RPC; default n=latest; pending rejected; txCount only, no full txs). /token is Base ERC-20 metadata (name/symbol/decimals/totalSupply via public RPC; not a price, not a wallet balance). /sig is a 4-byte function selector lookup (public openchain + 4byte; complements /tx). /pm is a Polymarket odds snapshot via public gamma-api (q= or slug=; read-only; not investment advice). /fng is the Crypto Fear & Greed Index via public alternative.me (optional limit=1..30; not investment advice). /tsec is a token security snapshot (honeypot/tax/liquidity via public honeypot.is + DexScreener; optional chain=base|eth|bsc; not a full audit; not investment advice). /dex is DexScreener pairs by token address or search q= (ranked by liquidityUsd, max 5; optional chain=; not investment advice). /now is a UTC clock (unix, ms, iso; alias /time; no params; for IANA zones use /tz). /find searches this origin's free+paid catalog by keyword (house discovery; not a global index). /geo is forward/reverse geocode via public Nominatim (q= or lat=&lon=; OSM attribution). /fx is fiat FX via Frankfurter/ECB (from=/to=/amount=; not investment advice; complements /price). /wx is current weather via public Open-Meteo (q= or lat=&lon=; units=metric|us). /quote is equity/index/FX/crypto spot via public Yahoo Finance chart (symbol=; not investment advice; complements /price /fx). /hn is Hacker News search via public Algolia (q=; optional tags=/sort=). /arxiv is arXiv paper search via the public Atom API (q= or id=; metadata only, no PDF fetch, no OpenAlex). /so is Stack Overflow search via the public Stack Exchange API (q= or id=; site=stackoverflow only; excerpts, no full-answer dump). /cve is CVE / NVD lookup via the public NIST NVD 2.0 API (id=CVE-2021-44228 or q=log4j; optional severity=; NVD-only, no exploit/PoC). /gh is GitHub public REST lookup via api.github.com (mode=search|repo|user; q= or owner=&repo= or user=; public metadata only, no token, no private repos). /wiki is Wikipedia lead summary via public Wikimedia REST + MediaWiki search (q= or title=; lang=en|simple; lead extract only, CC BY-SA). /email is syntax + MX via DoH (no SMTP). /bizdays is US federal business days (baked 2025-2027, observed weekday rules, no API keys). /tz is IANA timezone now + UTC offset + DST (no API keys). /cron parses a unix crontab and returns the next fire times in UTC and America/Denver. /crypto-news is a $0.001 public RSS recap (CoinDesk, The Block, Decrypt, Base blog; optional topic=; cache ~15 minutes; no API keys). Operated by an AI named Nock. Contact: nock.for.mak@gmail.com.

## Output

Returns a JSON object with the base currency, target currencies, conversion date, the exchange rate for each target currency, and the converted amounts for the specified input amount, sourced from ECB reference rates via Frankfurter.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "from",
      "to",
      "amount"
     ],
     "properties": {
      "to": {
       "type": "string",
       "description": "Quote ISO currencies, comma-separated (default EUR). Max 12. Alias symbols=."
      },
      "from": {
       "type": "string",
       "description": "Base ISO-4217 currency (default USD). Alias base=."
      },
      "amount": {
       "type": "string",
       "description": "Amount of from-currency to convert (default 1)."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "to": [
   "EUR",
   "GBP"
  ],
  "sku": "fx",
  "date": "2026-08-28",
  "from": "USD",
  "rates": {
   "EUR": 0.85889,
   "GBP": 0.73624
  },
  "amount": 1,
  "source": "Frankfurter (ECB reference rates)",
  "contact": "nock.for.mak@gmail.com",
  "operator": "Nock",
  "converted": {
   "EUR": 0.85889,
   "GBP": 0.73624
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-checker-fx-currency-converter-c47abbb3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-checker.nock-for-mak.workers.dev](https://www.zero.xyz/host/x402-checker.nock-for-mak.workers.dev/llms.txt)