Streamable HTTP (Backend)

The Streamable HTTP transport is the primary protocol for HTTP backends. It supports:

• Non-streaming mode: Client sends requests, server responds synchronously
• Streaming mode: Server streams notifications and results as they become available
• Batch messages: Multiple JSON-RPC messages in a single HTTP request

Configuration

// Enabled by default when using create_axum_server / create_actix_server
// No additional configuration needed beyond the basic server options.

// To disable Streamable HTTP and only support SSE (not recommended):
// (There's no explicit flag - just set sse_support: true and don't use Streamable HTTP)

Client-side

use rust_mcp_sdk::{
    mcp_client::{client_runtime, ClientHandler},
    RequestOptions, StreamableTransportOptions,
};

// Connect to the running server over Streamable HTTP
let transport_options = StreamableTransportOptions {
    mcp_url: "http://127.0.0.1:8080/mcp".into(),
    request_options: RequestOptions {
        ..Default::default()
    },
};

// create the MCP client (`client_details` is an `InitializeRequestParams`,
// `handler` implements `ClientHandler`)
let client = client_runtime::with_transport_options(
    client_details,
    transport_options,
    handler,
    None,
    None,
    None,
);