frankfurter-mcp

Official Model Context Protocol server for the Frankfurter exchange-rate API. A thin, stateless proxy over Frankfurter's v2 blended multi-source reference rates.

Tools

• convert — the primary tool. Convert an amount between two currencies; returns a money object { amount, currency } rounded to the target's minor units. Pass date for a historical rate, provider for one institution's published rate (e.g. UST, the U.S. Treasury's quarterly reporting rate).
• get_rates — blended reference rates for the latest day or a single date. Optional base, quotes and provider. The raw-rate companion to convert; with provider and the provider's own base, the digits are as published, with the date they took effect.
• list_currencies — supported ISO 4217 codes and names as { code: name }.
• list_providers — the institutions relayed, with key, rate type, frequency and coverage dates, to pick a provider.

For time series, historical ranges, or bulk queries, use the REST API at https://api.frankfurter.dev/v2 directly.

Rates are daily reference rates, not real-time trading rates. Not financial advice.

Run

npm install
npm run build
npm start            # listens on :3000, POST /

Docker:

docker build -t frankfurter-mcp . && docker run -p 3000:3000 frankfurter-mcp
docker run -p 3000:3000 ghcr.io/lineofflight/frankfurter-mcp:latest

The prebuilt ghcr.io/lineofflight/frankfurter-mcp:latest image is published on each release; building from source also works.

Point any MCP client at http://<host>:3000/ (Streamable HTTP). The hosted server is at https://mcp.frankfurter.dev/.

Configuration

• PORT — HTTP port (default 3000).
• FRANKFURTER_API_URL — upstream API base (default https://api.frankfurter.dev). Set this to a self-hosted Frankfurter instance if desired. The value must be a host root: any path prefix in it is discarded (e.g. https://example.com/api resolves to https://example.com/v2/rates), so a self-hosted instance must be reachable at the host root.

Development

npm test       # vitest
npm run lint   # biome

License

MIT