Tools · finance

FX rates + conversion (live, with the ECB rate beside it)

Live exchange rates and a conversion for ~170 currencies and the major crypto assets, with the European Central Bank reference rate beside each live one and the deviation between them - an independent check in the same answer. {from, to, amount}; send {} for USD against eight majors. Pay-per-call via x402.

$0.001 per call, paid in USDC on Base or Solana with x402 — no account, no API key. POST https://fiatdock.com/v1/fx/rates (or GET with the same fields as query parameters) · MCP tool fx_rates. An answer the tool cannot produce is refused with 4xx/5xx and is not charged.

Inputs

Field	Type	Description	Example
`from`	string	Currency to convert FROM (ISO code like USD, EUR, or a crypto like BTC), default USD	`"USD"`
`to`	string	Currencies to convert TO, up to 20 (default EUR,GBP,JPY,CNY,CHF,CAD,AUD,INR) (comma-separated, or a JSON array)	`"EUR,GBP"`
`amount`	number	Amount of the FROM currency to convert (default 1)	`100`

Example

Request body

{"from":"USD","to":"EUR,GBP","amount":100}

Answer (the published example)

{"from":"USD","amount":100,"rates":[{"to":"EUR","rate":0.851,"converted":85.1,"ecbRate":0.8512,"deviationFromEcbPct":-0.024},{"to":"GBP","rate":0.742,"converted":74.2,"ecbRate":0.7419,"deviationFromEcbPct":0.013}],"ecbDate":"2026-10-02","source":"Coinbase exchange rates (live mid) + ECB reference rates via Frankfurter","asOf":"2026-10-05T00:00:00.000Z","note":"rate = units of each target one USD buys (a mid rate, before any spread or fee)."}

Call it

curl

# 1) ask: an unpaid call answers 402 with the exact price (free)
curl -i -X POST https://fiatdock.com/v1/fx/rates -H 'content-type: application/json' -d '{"from":"USD","to":"EUR,GBP","amount":100}'
# 2) pay: any x402 client signs that 402 and resends — see Node or Python below

Node

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

const pay = wrapFetchWithPaymentFromConfig(fetch, {
  schemes: [{ network: "eip155:*", client: new ExactEvmScheme(privateKeyToAccount(process.env.AGENT_PRIVATE_KEY)) }],
});
const r = await pay("https://fiatdock.com/v1/fx/rates", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({"from":"USD","to":"EUR,GBP","amount":100}),
});
console.log(r.status, await r.json());

Python

# pip install "x402[httpx,evm]"
import asyncio, json, os
from eth_account import Account
from x402 import x402Client
from x402.http.clients import x402HttpxClient
from x402.mechanisms.evm.exact import register_exact_evm_client

async def main():
    client = register_exact_evm_client(x402Client(), Account.from_key(os.environ["AGENT_PRIVATE_KEY"]))
    async with x402HttpxClient(client) as http:
        r = await http.post("https://fiatdock.com/v1/fx/rates", json=json.loads("{\"from\":\"USD\",\"to\":\"EUR,GBP\",\"amount\":100}"))
        print(r.status_code, r.json())

asyncio.run(main())

MCP (Claude, Cursor, any MCP client)

{"mcpServers":{"fiatdock":{"command":"npx","args":["-y","fiatdock-mcp"],"env":{"AGENT_PRIVATE_KEY":"0x<your agent wallet key>"}}}}
// then call the tool "fx_rates" — the package pays each call from that wallet

The wallet needs USDC on Base. Prefer no install? The remote server https://fiatdock.com/mcp answers the 402 as tool output for an agent that signs its own payments.

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Machine-readable: OpenAPI · tools.json · llms.txt · /.well-known/x402