# Transports (/docs/configuration/transports)

## HTTP transport

xmcp servers speak both current MCP protocol generations over Streamable HTTP: requests carrying the [2026-07-28](https://modelcontextprotocol.io/specification/2026-07-28) per-request `_meta` envelope (including `server/discover`) are served natively, and 2025-era clients that start with the classic `initialize` handshake are served through the stateless fallback. Both paths build a fresh server per request — no session state survives between requests.

The `http` configuration customizes the HTTP server. Set it to `true` to use defaults, or provide an object to override specific options:

```typescript title="xmcp.config.ts"
const config: XmcpConfig = {
  http: {
    port: 3001,
    host: "127.0.0.1",
    endpoint: "/mcp",
    bodySizeLimit: 10485760, // 10MB
    debug: false, // adds extra logging to the console
  },
};

export default config;
```

These are the default values. Override only what you need to customize.

### CORS

CORS (Cross-Origin Resource Sharing) middleware that can be configured to control cross-origin requests.

```typescript title="xmcp.config.ts"
const config: XmcpConfig = {
  http: {
    cors: {
      origin: "*",
      methods: ["GET", "POST"],
      allowedHeaders: [
        "Content-Type",
        "Authorization",
        "mcp-session-id",
        "mcp-protocol-version",
        "mcp-method",
        "mcp-name",
        "x-mcp-client-name",
        "x-mcp-client-version",
        "x-mcp-client-title",
        "x-mcp-client-website-url",
        "x-mcp-client-description",
      ],
      exposedHeaders: ["Content-Type", "Authorization", "mcp-session-id"],
      credentials: false,
      maxAge: 86400,
    },
  },
};

export default config;
```

## STDIO transport

The `stdio` configuration customizes the STDIO transport. Set it to `true` to use defaults, or provide an object to override specific options:

By default you enable STDIO transport by setting it to `true`.

```typescript title="xmcp.config.ts"
const config: XmcpConfig = {
  stdio: true,
};
```

You can also customize the debug mode and this would enable it as well.

```typescript title="xmcp.config.ts"
const config: XmcpConfig = {
  stdio: {
    debug: false, // adds extra logging to the console
  },
};
```

### Silent mode

When using STDIO transport, any `console.log`, `console.debug`, `console.info`, `console.warn`, or `console.error` calls in your tool handlers will write to stdout, which interferes with the MCP protocol. Enable `silent` to automatically redirect all console output to stderr instead:

```typescript title="xmcp.config.ts"
const config: XmcpConfig = {
  stdio: {
    silent: true,
  },
};
```

This is useful when your tools or dependencies contain debug logs that would otherwise corrupt the MCP communication. The logs are not lost, they are still visible in stderr.

## Troubleshooting

Keep in mind that clients like Claude Desktop are not compatible with STDIO logging and would cause a JSON parsing error. You can use the `silent` option to redirect console output to stderr and avoid this issue.