> ## Documentation Index
> Fetch the complete documentation index at: https://seilabs-pr-registry-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Transport Modes

> Understanding MCP transport protocols and when to use each

The Sei MCP Server supports three transport modes for different integration scenarios. In most cases, `stdio` is the best choice, but understanding these modes is important if you need a remote MCP server or if your AI tool doesn't support MCP. Each transport offers unique advantages depending on your use case and client requirements.

## Transport Overview

<CardGroup cols={1}>
  <Card title="stdio" icon="terminal">
    **Default Mode**
    Direct process communication via standard input/output streams.
  </Card>

  <Card title="streamable-http" icon="globe">
    **HTTP API**
    RESTful HTTP server with streaming capabilities for web integrations.
  </Card>

  <Card title="http-sse (deprecated)" icon="wifi-slash">
    **Server-Sent Events**
    HTTP with server-sent events (deprecated, use streamable-http instead).
  </Card>
</CardGroup>

## Choosing the Right Transport

<AccordionGroup>
  <Accordion title="stdio - Best for Cursor, Windsurf, & local clients" icon="terminal">
    **Recommended for:**

    * Claude Desktop, Cursor, Windsurf integrations
    * Local development and testing
    * Maximum performance requirements

    **Pros:**

    * Fastest performance (no network overhead)
    * Automatic lifecycle management
    * Native MCP client support

    **Cons:**

    * Limited to local process communication
    * No remote access capabilities

    **Security:**

    * Process isolation (server runs as child process)
    * No network exposure (communication via local IPC)
    * Client-managed lifecycle
  </Accordion>

  <Accordion title="streamable-http - Best for remote access or tools that don't support MCP" icon="globe">
    **Recommended for:**

    * Remote server deployments
    * Custom HTTP clients
    * Tools that don't support MCP
    * Web applications

    **Pros:**

    * Network accessible
    * Standard HTTP protocols
    * Scalable and load-balanceable
    * Works with any HTTP client

    **Cons:**

    * Network latency overhead
    * Requires manual server management
    * Additional security considerations

    **Security:**

    * Network exposure (server accessible over HTTP)
    * Consider implementing API keys or tokens
    * Configure CORS policies as needed
    * Restrict access to trusted networks
    * Use reverse proxy with HTTPS for production
  </Accordion>

  <Accordion title="http-sse - Deprecated, use streamable-http instead" icon="wifi-slash">
    **Status:** Deprecated - migrate to `streamable-http`

    This transport is no longer recommended for new implementations. Existing users should migrate to `streamable-http` for better performance and standards compliance.
  </Accordion>
</AccordionGroup>

***

## Configuration

<Tabs>
  <Tab title="stdio">
    ```json Claude Desktop theme={null}
    {
      "mcpServers": {
        "sei": {
          "command": "npx",
          "args": ["-y", "@sei-js/mcp-server"]
        }
      }
    }
    ```

    ```bash Environment Variables theme={null}
    # stdio is the default, no configuration needed
    SERVER_TRANSPORT=stdio  # Optional, this is default
    npx @sei-js/mcp-server
    ```
  </Tab>

  <Tab title="streamable-http">
    ```bash Basic Setup theme={null}
    SERVER_TRANSPORT=streamable-http npx @sei-js/mcp-server
    ```

    Defaults to `http://localhost:8080/mcp`

    ```bash Custom Configuration theme={null}
    SERVER_TRANSPORT=streamable-http \
    SERVER_PORT=3001 \
    SERVER_HOST=0.0.0.0 \
    SERVER_PATH=/api/sei \
    npx @sei-js/mcp-server
    ```

    Runs on `http://0.0.0.0:3001/api/sei`

    ```json MCP Client Config theme={null}
    {
      "mcpServers": {
        "sei": {
          "command": "npx",
          "args": ["-y", "@sei-js/mcp-server"],
          "env": {
            "SERVER_TRANSPORT": "streamable-http",
            "SERVER_PORT": "8080"
          }
        }
      }
    }
    ```

    ```bash Test with curl theme={null}
    # Get available tools
    curl -X POST http://localhost:8080/mcp \
      -H "Content-Type: application/json" \
      -H "Accept: application/json, text/event-stream" \
      -d '{"jsonrpc": "2.0", "id": 1, "method": "tools/list"}'

    # Call a specific tool (example: get balance)
    curl -X POST http://localhost:8080/mcp \
      -H "Content-Type: application/json" \
      -H "Accept: application/json, text/event-stream" \
      -d '{"jsonrpc": "2.0", "id": 2, "method": "tools/call", "params": {"name": "get_balance", "arguments": {"address": "0x1234..."}}}'
    ```
  </Tab>

  <Tab title="http-sse">
    <Warning>
      **Deprecated**: Migrate to `streamable-http` instead.
    </Warning>

    ```bash theme={null}
    SERVER_TRANSPORT=http-sse npx @sei-js/mcp-server
    ```
  </Tab>
</Tabs>

***