> ## Documentation Index > Fetch the complete documentation index at: https://mcpgolang.com/llms.txt > Use this file to discover all available pages before exploring further. # Architecture > mcp-golang library architecture The library is split functionally into three distinct components which mimic the architecture of the MCP protocol itself: * **The transport layer** - which handles the actual communication between the client. This could be a TCP connection, an HTTP request, or a WebSocket connection or anything else. It is reponsible for taking those underlying messages and converting them to JSON-RPC messages and taking JSON-RPC messages and converting them to underlying messages. * **The protocol layer** - which defines the actual protocol for the transport layer, it takes JSON-RPC messages and turns them into requests, notifications, and responses. It also has a list of handlers which handle requests and notifications, it performs the JSON-RPC method routing and error handling. * **The server layer** - which is the actual implementation of the server, it takes the protocol layer and the transport layer and builds a server that can handle requests from clients. It offers a much higher level API to the user where they can register basic handlers for tools, resources, prompts, completions, etc. * **The user code** itself, which are handlers. These handlers implement the business logic for the tools, resources, prompts, completions, etc and are passed to the server layer. MCP Golang architecture diagram