MCP Transport (stdio/Streamable HTTP/sse)

Welcome back. When you use an MCP server you usually do not care which transport moves the data. That detail matters only if you build the server yourself. A project can rely on one transport or several, so it helps to know how each one works. All three transports use JSON RPC 2.0 to shape requests and replies, which keeps traffic clear and easy to debug. First comes SDIO, short for standard input and output. The server runs on your machine as a subprocess and talks through the local stream, so no network or login is needed. This setup suits a single user who links the AI with local tools such as the file system, the browser log, or a private database. It is the fastest path for experiments and personal scripts. Streamable HTTP runs on a remote server that waits for HTTPS calls. Every user sends a request and the server streams the reply as soon as parts of it are ready. The text appears bit by bit, which feels quick, like a chat window. This model fits cloud tools and teams that need secure access and token based control. Older projects may still use SSE, or Server Sent Events. In that model the client sends one request and the server pushes many updates over a single HTTP stream. It worked fine for simple cases, yet it struggled with many users and complex logic. Streamable HTTP replaced it, yet SSE stays as a safe fallback so old software keeps running. Streaming itself means the server does not wait until the full answer is built. With SDIO you see nothing until the message is finished. With Streamable HTTP letters appear live, like watching someone type in a shared document. The feature makes long answers feel faster and more natural. When you compare SDIO and Streamable HTTP think about scope, security, and effort. SDIO is local, simple, and perfect for command line tools. Streamable HTTP can be local or remote, uses tokens or headers for safety, and suits cloud services. Building SDIO is lighter; setting up Streamable HTTP takes more work but scales to many users. Cursor lets you declare each server in the mcp.json file. For an SDIO server you list the command that starts the subprocess. For Streamable HTTP or SSE you give a URL and any auth headers. Some command line apps can switch among all three with a flag, so one package covers every transport. That covers the transport layer for MCP. Thanks for watching. If you have questions ask me any time. See you in the next video. Bye.