UniRate MCP Server

A Model Context Protocol server for the UniRate API — give Claude, Cursor, Continue, and any MCP-compatible AI assistant first-class access to currency conversion and exchange rates.

• 🔄 Real-time conversion between 170+ currencies (fiat + major crypto)
• 📈 Historical rates back to 1999 (Pro plan)
• 🆓 Free tier, no credit card required — get a key at unirateapi.com
• 🧩 Four tools, fully-typed inputs (Zod schemas), structured outputs
• 🌐 Stdio + Streamable HTTP/SSE transports — run locally or host as a remote MCP endpoint
• ⚡ Pure Node 18+, single dependency on @modelcontextprotocol/sdk

Why this exists

Most "currency for AI" workflows today involve hand-rolled fetch wrappers in custom tools, or generic HTTP MCP servers that hand the model raw JSON. This server gives models a tight, typed, currency-aware tool surface — they ask "what was 100 USD in EUR on 2020-03-15?" and get back a formatted answer plus a structured payload they can chain into other tool calls.

Quick start

1. Install

npm install -g @unirate/mcp

Or run on demand with npx @unirate/mcp (no install).

2. Get a UniRate API key

Free tier covers convert, latest_rate, and list_currencies. Sign up at unirateapi.com — no credit card required.

3. Wire it into your MCP client

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "unirate": {
      "command": "npx",
      "args": ["-y", "@unirate/mcp"],
      "env": {
        "UNIRATE_API_KEY": "your-api-key-here"
      }
    }
  }
}

Restart Claude Desktop. The four UniRate tools will appear in the tool picker.

Cursor / Continue / Cline

Add to your MCP config (.cursor/mcp.json, ~/.continue/config.json, etc.):

{
  "mcpServers": {
    "unirate": {
      "command": "npx",
      "args": ["-y", "@unirate/mcp"],
      "env": { "UNIRATE_API_KEY": "your-api-key-here" }
    }
  }
}

From source

git clone https://github.com/UniRate-API/unirate-mcp.git
cd unirate-mcp
npm install && npm run build
UNIRATE_API_KEY=your-key node dist/index.js

4. Run as a remote endpoint (Streamable HTTP / SSE)

By default the server uses stdio, which is what Claude Desktop and most MCP clients want. To host it as a remote endpoint instead — for shared use, multi-user deployments, or browser-based clients — start it in HTTP mode:

UNIRATE_API_KEY=your-key unirate-mcp --http 3001
# or via env:
UNIRATE_API_KEY=your-key UNIRATE_MCP_HTTP_PORT=3001 unirate-mcp

That exposes:

• POST /mcp — Streamable HTTP endpoint (SSE-capable). Stateless: a fresh server is built per request, so the same process can serve many concurrent clients.
• GET /healthz — JSON liveness probe ({ "status": "ok", "server": "unirate-mcp", "version": "..." }).

Point any Streamable-HTTP-capable MCP client (Claude Desktop with remote server support, Cursor remote MCP, etc.) at http://your-host:3001/mcp. Drop it behind a reverse proxy + TLS for production.

Programmatic / edge runtimes (Cloudflare Workers, Deno, Bun)

The package exports buildServer(client) so you can wire it to whatever transport your runtime prefers. For Workers / Deno / Bun, use the SDK's webStandardStreamableHttp transport with an exported buildServer instance.

import { UnirateClient } from "@unirate/mcp/dist/client.js";
import { buildServer } from "@unirate/mcp";
// → connect to your runtime's preferred transport

Tools

convert

Convert an amount from one currency to another at the latest rate.

Param	Type	Required	Notes
from	string	yes	ISO 4217 code (e.g. USD)
to	string	yes	ISO 4217 code (e.g. EUR)
amount	number	yes	Positive amount in from

Example call:

{ "name": "convert", "arguments": { "from": "USD", "to": "EUR", "amount": 100 } }

Response: human-readable text plus structured { from, to, amount, result }.

latest_rate

Get current exchange rate(s).

Param	Type	Required	Notes
from	string	yes	Base currency
to	string	no	Target. Omit to get rates for all currencies

historical_rate (Pro plan)

Get the exchange rate that was in effect on a specific date. Coverage back to 1999-01-04 for major fiat pairs.

Param	Type	Required	Notes
date	string	yes	YYYY-MM-DD (e.g. 2020-03-15)
from	string	yes	Source currency
to	string	yes	Target currency
amount	number	no	Defaults to 1

Free-tier keys receive a clear error pointing to unirateapi.com for upgrade.

list_currencies

Returns the array of supported currency codes (170+) with no parameters. Useful for autocomplete or validating user-supplied codes.

Errors

All UniRate API failures are mapped to friendly tool errors:

HTTP	Error class	What the model sees
400	InvalidRequestError	"Invalid request parameters"
401	AuthenticationError	"Missing or invalid API key"
403	ProPlanRequiredError	"…requires Pro… upgrade at https://unirateapi.com"
404	InvalidCurrencyError	"Currency not found or no data available"
429	RateLimitError	"Rate limit exceeded"
503	APIError	"Service unavailable"

Network/timeout errors are wrapped in UnirateError. Tool calls always return a response object with isError: true rather than throwing protocol-level errors, so the model can recover gracefully.

Development

npm install
npm run build       # compile TypeScript to dist/
npm test            # 24 mock tests
UNIRATE_LIVE=1 UNIRATE_API_KEY=... npm run test:live  # +4 live free-tier tests

Related projects

UniRate offers official client libraries in 9 languages:

• Python (pip install unirate-api)
• Node.js (npm install unirate-api)
• Swift
• Java
• Go
• Rust
• Ruby
• PHP
• .NET

Plus an n8n community node.

License

MIT — see LICENSE.