Convert an amount between currencies at a live or historical exchange rate. Pass from + to (3-letter ISO 4217 codes) and optional amount (default 1) and date (YYYY-MM-DD for a historical rate; omit for the latest). Returns the converted result, the per-unit rate, and the effective rate date. Live data from the European Central Bank reference rates (via Frankfurter) — fetched per request, never stale; weekends/holidays use the last published business day. Coverage is the ECB major currencies. Distinct from fx.rates (the raw rate table) — this is the agent-friendly "X from = ? to" call.
/api/convert/currencyPAYMENT-SIGNATURE.The currency API is a pay-per-call convert endpoint built for AI agents and autonomous software. Convert an amount between currencies at a live or historical exchange rate.
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 currency data source for an agent tool-use loop, an MCP host, or a backend that needs convert data on demand without onboarding to yet another vendor portal.
| Name | Type | Description |
|---|---|---|
fromrequired | string | min 3 chars · max 3 chars |
torequired | string | min 3 chars · max 3 chars |
amount | number | min 0 |
date | string | match ^\d{4}-\d{2}-\d{2}$ |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/convert/currency?from=xxx&to=xxx&amount=0&date=2024-01-01' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/convert/currency?from=xxx&to=xxx&amount=0&date=2024-01-01' \ -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/convert/currency?from=xxx&to=xxx&amount=0&date=2024-01-01'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.convert.currency({
"from": "xxx",
"to": "xxx",
"amount": 0,
"date": "2024-01-01"
})
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.convert.currency(from="xxx", to="xxx", amount=0, date="2024-01-01")
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": "convert.currency",
"arguments": {
"from": "xxx",
"to": "xxx",
"amount": 0,
"date": "2024-01-01"
}
}
}| Field | Type | Description |
|---|---|---|
query | object | |
rateDate | string | |
rate | number | |
result | number | |
source | object |
{
"query": {
"from": "example",
"to": "example",
"amount": 1,
"date": "example"
},
"rateDate": "example",
"rate": 1,
"result": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
}
}