Transport Configuration

---

title: "Transport Configuration" description: "Complete reference for MCP transport protocols in mcp-framework — stdio for local processes and SSE for remote HTTP servers, with CORS and endpoint configuration." order: 7 keywords: ["MCP transport", "stdio", "SSE", "Server-Sent Events", "transport configuration", "MCP HTTP", "mcp-framework transport"] date: "2026-04-01"

Transport Overview

stdio Transport

The default transport. Communication happens via stdin (incoming messages) and stdout (outgoing messages). This is what Claude Desktop and Cursor use when running MCP servers as local processes.

Configuration

import { MCPServer } from "mcp-framework";

// Explicit stdio (same as default)
const server = new MCPServer({
  transport: {
    type: "stdio",
  },
});

server.start();

Or simply use the default:

const server = new MCPServer();
server.start();

When to Use stdio

• Local development with Claude Desktop or Cursor
• Running the MCP server as a subprocess
• Single-client scenarios
• Maximum simplicity

SSE Transport

Server-Sent Events transport enables HTTP-based communication. The server starts an HTTP listener with two endpoints:

• GET /sse — Client connects here to receive server-sent events (server-to-client messages)
• POST /messages — Client sends messages here (client-to-server messages)

Basic SSE Configuration

import { MCPServer } from "mcp-framework";

const server = new MCPServer({
  transport: {
    type: "sse",
    options: {
      port: 8080,
    },
  },
});

server.start();

Full SSE Configuration

import { MCPServer } from "mcp-framework";

const server = new MCPServer({
  transport: {
    type: "sse",
    options: {
      port: 8080,
      endpoint: "/sse",           // SSE connection endpoint
      messageEndpoint: "/messages", // Message receiving endpoint
      cors: {
        allowOrigins: ["https://myapp.com", "https://admin.myapp.com"],
      },
    },
  },
});

server.start();

SSE Options Reference

CORS Configuration

cors: {
  allowOrigins: ["https://myapp.com"],  // Allowed origins
}

When to Use SSE

• Remote/hosted MCP servers
• Multiple clients connecting simultaneously
• Web application integrations
• When you need HTTP-based authentication
• Deploying to cloud platforms

Transport Comparison

Environment-Based Configuration

A common pattern for supporting both transports:

import { MCPServer } from "mcp-framework";

const transport = process.env.MCP_TRANSPORT === "sse"
  ? {
      type: "sse" as const,
      options: {
        port: parseInt(process.env.PORT || "8080"),
        cors: {
          allowOrigins: process.env.CORS_ORIGINS?.split(",") || [],
        },
      },
    }
  : { type: "stdio" as const };

const server = new MCPServer({ transport });
server.start();

Connecting Clients

stdio — Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "my-server": {
      "command": "node",
      "args": ["/path/to/dist/index.js"]
    }
  }
}

SSE — HTTP Connection

For SSE servers, clients connect via HTTP:

Server URL: http://localhost:8080
SSE Endpoint: GET http://localhost:8080/sse
Messages: POST http://localhost:8080/messages