Zippopotam

What the zippopotam MCP server does

The zippopotam MCP server exposes postal-code lookups through the Model Context Protocol. It connects to the Zippopotam.us API and covers ZIP and postal codes in more than 60 countries.

Its two pack-specific tools address opposite lookup directions:

• lookup_zipcode resolves a country and ZIP or postal code to place information, including city, state or province, and latitude/longitude.
• lookup_city returns postal codes for a city when given its country and state or province.

Country and regional values can be supplied as names or codes. For example, the city lookup accepts either “California” or “CA,” and either “United States” or “US.” The ZIP lookup is appropriate for questions such as identifying the city for a postal code or obtaining coordinates for a location.

How it works

The zippopotam MCP server can be reached in two ways. A hosted MCP endpoint is available through Pipeworx at https://gateway.pipeworx.io/zippopotam/mcp. That scoped endpoint lists the two postal-code tools along with Pipeworx shared meta-tools. The gateway also offers ask_pipeworx, which can route plain-language requests across its broader catalog.

A full Pipeworx connection is available at https://gateway.pipeworx.io/mcp. Both hosted URLs use the same gateway and data sources; the difference is which pack's tools appear directly in the tool list. The gateway documentation notes that its initialization response is the authoritative source for the exact tool scope at a given time.

For applications that do not use an MCP client, the gateway exposes HTTP tool calls. For example, a client can send a JSON POST request to /v1/tools/lookup_zipcode with country and zipcode fields.

Setup and configuration

Add the hosted endpoint to an MCP client that supports remote MCP connections. The README gives examples for Claude Desktop, Cursor, and Windsurf. No account is needed for the first gateway calls, and the service does not require authentication for the postal-code API.

The package can also run locally over stdio with:

{
  "mcpServers": {
    "zippopotam": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-zippopotam"]
    }
  }
}

Running npx -y @pipeworx/mcp-zippopotam starts the local server. In standalone mode, it responds to MCP initialization, tool-listing, and tool-call requests for the pack's own tools only. It does not add the gateway's shared meta-tools or require a Pipeworx account.

Tools and capabilities

Use lookup_zipcode when a workflow starts with a postal code and needs a city, state or province, or geographic coordinates. Use lookup_city when a workflow starts with a city and needs all matching postal codes. The resulting location data can then be passed to downstream services, such as weather or property tools, when those services are available in the surrounding workflow.

The hosted lookup is described as free and sub-second in the provided material. The local package uses the same pack tools without a gateway round trip.

Limitations and notes

The server is focused on postal-code data. It does not itself provide weather, property, or other downstream data; those require separate tools or gateway routing. Hosted pack connections include shared Pipeworx schemas, so their visible tool count is larger than the two tools documented here. Use the local stdio package when only the postal-code tools are needed.