---
slug: "currency-converter-fiat-crypto-cross-rates"
source_type: "readme"
source_url: "https://cdn.jsdelivr.net/gh/Br0ski777/currency-converter-x402@master/README.md"
repo: "https://github.com/Br0ski777/currency-converter-x402"
source_file: "README.md"
branch: "master"
---
# Currency Converter API

[![MCP Server](https://img.shields.io/badge/MCP-server-blue)](https://currency-converter.api.klymax402.com/mcp)
[![x402](https://img.shields.io/badge/payments-x402-6E56CF)](https://x402.org)
[![License: MIT](https://img.shields.io/badge/license-MIT-green)](LICENSE)

Fiat and crypto currency converter -- ECB rates for fiat, CoinGecko for crypto. Instant cross-rate lookup. Pay-per-call via [x402](https://x402.org) (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the [klymax402](https://klymax402.com) marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

## Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

```json
{
  "mcpServers": {
    "currency-converter": {
      "url": "https://currency-converter.api.klymax402.com/mcp"
    }
  }
}
```

## Quickstart -- HTTP (x402)

```bash
curl -X POST "https://currency-converter.api.klymax402.com/api/convert" \
  -H "Content-Type: application/json" \
  -d '{"amount":"1","from":"...","to":"..."}'
# -> 402 Payment Required, with an x402 payment challenge in the response body
```

Any x402-aware client ([`@x402/fetch`](https://www.npmjs.com/package/@x402/fetch), [`x402-agent-tools`](https://www.npmjs.com/package/x402-agent-tools), ATXP) handles the 402 -> sign -> retry cycle automatically.

## Tools

| Tool | Method | Path | Price | Description |
|---|---|---|---|---|
| `finance_convert_currency` | POST | `/api/convert` | $0.003 | Convert between fiat currencies and cryptocurrencies |

### `finance_convert_currency`

Use this when you need to convert between any currencies -- both fiat (USD, EUR, GBP, JPY) and crypto (BTC, ETH, SOL). Returns conversion result in JSON.

**Parameters**

| Name | Type | Required | Description |
|---|---|---|---|
| `amount` | number | yes | Amount to convert |
| `from` | string | yes | Source currency code (e.g., USD, EUR, BTC, ETH) |
| `to` | string | yes | Target currency code (e.g., EUR, GBP, USD, BTC) |

**Returns**

- `convertedAmount` -- the resulting amount in target currency
- `exchangeRate` -- the rate used for conversion
- `from` -- source currency code
- `to` -- target currency code
- `amount` -- original amount provided
- `rateSource` -- data source used (ECB for fiat, CoinGecko for crypto)
- `timestamp` -- when the rate was fetched

Example response:

```json
{"convertedAmount":2815.40,"exchangeRate":0.9218,"from":"USD","to":"EUR","amount":3054.00,"rateSource":"ECB","timestamp":"2026-04-13T12:00:00Z"}
```

**When to use**: price conversions across fiat and crypto in a single call. Essential for international pricing, invoice generation, and portfolio valuation in local currency.

**Not for**: market data or charts (use `finance_get_token_price`), DeFi swap quotes (use `dex_get_swap_quote`), wallet balances (use `wallet_get_portfolio`).

## Example agent prompts

- "Convert between any currencies -- both fiat (USD, EUR, GBP, JPY) and crypto (BTC, ETH, SOL)"

## Payment

- Protocol: [x402](https://x402.org) -- HTTP-native pay-per-call, no signup, no API key
- Network: Base L2 (`eip155:8453`)
- Asset: USDC
- Facilitator: Coinbase CDP (primary), PayAI (fallback)

## Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

- Catalog: https://klymax402.com/llms.txt
- Full API reference: https://klymax402.com/llms-full.txt
- Live stats: https://klymax402.com/stats

## License

MIT