Gateway MCP Server

Supergateway bridges transport protocols for MCP servers, enabling bidirectional conversion between stdio, SSE (Server-Sent Events), WebSockets, and Streamable HTTP. It exposes local MCP stdio servers over network protocols for remote access, or connects to remote SSE/Streamable HTTP endpoints and proxies them locally over stdio for debugging and development. Key capabilities: - Convert MCP stdio servers to SSE, WebSocket, or Streamable HTTP endpoints with configurable ports, base URLs, and path routes - Reverse proxy mode: connect to remote SSE servers and expose them locally over stdio - Support for custom headers, OAuth2 Bearer tokens, and CORS configuration - Health check endpoints and session timeout configuration for stateful Streamable HTTP connections - Compatible with hosted MCP platforms including Supermachine, Superinterface, and Supercorp

Supergateway runs MCP stdio-based servers over SSE (Server-Sent Events) or WebSockets (WS) with one command. This is useful for remote access, debugging, or connecting to clients when your MCP server only supports stdio.

Supported by Supermachine (hosted MCPs), Superinterface, and Supercorp.

Installation & Usage

Run Supergateway via npx:

npx -y supergateway --stdio "uvx mcp-server-git"

stdio → SSE

Expose an MCP stdio server as an SSE server:

npx -y supergateway \
    --stdio "npx -y @modelcontextprotocol/server-filesystem ./my-folder" \
    --port 8000 --baseUrl http://localhost:8000 \
    --ssePath /sse --messagePath /message

SSE → stdio

Connect to a remote SSE server and expose locally via stdio:

npx -y supergateway --sse "https://mcp-server-ab71a6b2-cd55-49d0-adba-562bc85956e3.supermachine.app"

Useful for integrating remote SSE MCP servers into local command-line environments.

You can also pass headers when sending requests. This is useful for authentication:

npx -y supergateway \
    --sse "https://mcp-server-ab71a6b2-cd55-49d0-adba-562bc85956e3.supermachine.app" \
    --oauth2Bearer "some-access-token" \
    --header "X-My-Header: another-header-value"

Streamable HTTP → stdio

Connect to a remote Streamable HTTP server and expose locally via stdio:

npx -y supergateway --streamableHttp "https://mcp-server.example.com/mcp"

This mode is useful for connecting to MCP servers that use the newer Streamable HTTP transport protocol. Like SSE mode, you can also pass headers for authentication:

npx -y supergateway \
    --streamableHttp "https://mcp-server.example.com/mcp" \
    --oauth2Bearer "some-access-token" \
    --header "X-My-Header: another-header-value"

stdio → Streamable HTTP

Expose an MCP stdio server as a Streamable HTTP server.

Stateless mode

npx -y supergateway \
    --stdio "npx -y @modelcontextprotocol/server-filesystem ./my-folder" \
    --outputTransport streamableHttp \
    --port 8000

Stateful mode

npx -y supergateway \
    --stdio "npx -y @modelcontextprotocol/server-filesystem ./my-folder" \
    --outputTransport streamableHttp --stateful \
    --sessionTimeout 60000 --port 8000

The Streamable HTTP endpoint defaults to http://localhost:8000/mcp (configurable via --streamableHttpPath).

stdio → WS

Expose an MCP stdio server as a WebSocket server:

npx -y supergateway \
    --stdio "npx -y @modelcontextprotocol/server-filesystem ./my-folder" \
    --port 8000 --outputTransport ws --messagePath /message

Example with MCP Inspector (stdio → SSE mode)

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