typescript-sdk/packages/middleware/node

@modelcontextprotocol/node

Node.js adapters for the MCP TypeScript server SDK.

This package is a thin Node.js integration layer for @modelcontextprotocol/server. It provides a Streamable HTTP transport that works with Node’s IncomingMessage / ServerResponse.

For web‑standard runtimes (Cloudflare Workers, Deno, Bun, etc.), use WebStandardStreamableHTTPServerTransport from @modelcontextprotocol/server directly.

Install

npm install @modelcontextprotocol/server @modelcontextprotocol/node

Exports

• NodeStreamableHTTPServerTransport
• StreamableHTTPServerTransportOptions (type alias for WebStandardStreamableHTTPServerTransportOptions)
• toNodeHandler(handler, opts?) — adapt a web-standard { fetch } MCP handler to a Node (req, res, parsedBody?) handler
• ToNodeHandlerOptions, FetchLikeMcpHandler, NodeMcpRequestHandler (types for toNodeHandler)
• toWebRequest(req, parsedBody?, opts?) — the Node IncomingMessage → web-standard Request conversion toNodeHandler performs internally, exported on its own (for example to feed isLegacyRequest() from a hand-wired (req, res) handler)
• ToWebRequestOptions (options type for toWebRequest)
• NodeIncomingMessageLike, NodeServerResponseLike (structural Node request/response shapes)

Usage

Express + Streamable HTTP

import { createMcpExpressApp } from '@modelcontextprotocol/express';
import { NodeStreamableHTTPServerTransport } from '@modelcontextprotocol/node';
import { McpServer } from '@modelcontextprotocol/server';

const server = new McpServer({ name: 'my-server', version: '1.0.0' });
const app = createMcpExpressApp();

app.post('/mcp', async (req, res) => {
    const transport = new NodeStreamableHTTPServerTransport({ sessionIdGenerator: undefined });
    await server.connect(transport);

    // If you use Express JSON parsing, pass the pre-parsed body to avoid re-reading the stream.
    await transport.handleRequest(req, res, req.body);
});

Node.js http server

import { createServer } from 'node:http';
import { NodeStreamableHTTPServerTransport } from '@modelcontextprotocol/node';
import { McpServer } from '@modelcontextprotocol/server';

const server = new McpServer({ name: 'my-server', version: '1.0.0' });

createServer(async (req, res) => {
    const transport = new NodeStreamableHTTPServerTransport({ sessionIdGenerator: undefined });
    await server.connect(transport);
    await transport.handleRequest(req, res);
}).listen(3000);