MCP Streamable HTTP transport

Streamable HTTP is the MCP remote transport. The client POSTs JSON-RPC requests to the server's HTTP endpoint; the server responds with the JSON-RPC response. For server-to-client messages (notifications, streaming responses), the server uses server-sent events (SSE) over a long-lived connection.

The client sends a POST request with a JSON-RPC message to the server URL. The server processes it and returns the response in the HTTP response body. For streaming, the client opens an SSE connection to receive notifications and long-running responses.

Remote servers must authenticate callers. The MCP specification supports OAuth-based authorization for protected resources. Bearer tokens are the common mechanism.

Streamable HTTP servers run as network services. They require a reachable URL, TLS in production, and proper authentication. They enable multi-user and remote access.