Daily reference exchange rates from the European Central Bank (via Frankfurter). 30+ major currencies. Pass base = 3-letter ISO 4217 currency (default USD), optional symbols = comma-separated target codes (default = all available), optional date = YYYY-MM-DD for historical rates (history back to 1999, business days only; omit for latest), optional amount to convert (default 1). Returns base, date, amount, and a map of currency code → rate.
/api/fx/ratesPAYMENT-SIGNATURE.The rates API is a pay-per-call fx endpoint built for AI agents and autonomous software. Daily reference exchange rates from the European Central Bank (via Frankfurter).
There is no signup and no API key. An agent (or any HTTP client) hits the endpoint, receives an x402 "402 Payment Required" challenge, signs a sub-cent USDC payment on Base or Solana, and retries — the data comes back on the paid request. That makes it a drop-in rates data source for an agent tool-use loop, an MCP host, or a backend that needs fx data on demand without onboarding to yet another vendor portal.
| Name | Type | Description |
|---|---|---|
base | string | match ^[A-Za-z]{3}$ |
symbols | string | min 3 chars · max 200 chars |
date | string | match ^\d{4}-\d{2}-\d{2}$ |
amount | number | min 0 · max 1000000000 |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/fx/rates?base=USD&symbols=xxx&date=2024-01-01&amount=1' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/fx/rates?base=USD&symbols=xxx&date=2024-01-01&amount=1' \ -H 'PAYMENT-SIGNATURE: <base64-json-payload>' # Or use the canonical runner (handles probe → sign → retry): # EVM_PRIVATE_KEY=0x... node --env-file=.env.local \ # --experimental-strip-types scripts/x402-pay.ts \ # 'https://2s.io/api/fx/rates?base=USD&symbols=xxx&date=2024-01-01&amount=1'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.fx.rates({
"base": "USD",
"symbols": "xxx",
"date": "2024-01-01",
"amount": 1
})
console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)import os
from twosio import TwoS
client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])
result = client.fx.rates(base="USD", symbols="xxx", date="2024-01-01", amount=1)
print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
// EVM_PRIVATE_KEY funds x402 payments per call.
// claude_desktop_config.json
{
"mcpServers": {
"2sio": {
"command": "npx",
"args": ["-y", "@2sio/mcp"],
"env": { "EVM_PRIVATE_KEY": "0x..." }
}
}
}
// 2. Once the server is running, agents call this tool via standard MCP:
{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/call",
"params": {
"name": "fx.rates",
"arguments": {
"base": "USD",
"symbols": "xxx",
"date": "2024-01-01",
"amount": 1
}
}
}| Field | Type | Description |
|---|---|---|
ok | boolean | one of: true |
items | array | |
total | integer | Total matching rows upstream; null when unknown. |
source | object | |
meta | object |
{
"ok": true,
"items": [
{
"currency": "example",
"rate": 1
}
],
"total": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
},
"meta": {
"base": "example",
"date": "example",
"amount": 1
}
}