MCP Server (Model Context Protocol Server) is a standardized framework that enables AI applications to securely connect with APIs, SQL databases, file systems, enterprise data, and other external data sources. Acting as the bridge between an MCP Client and backend systems, it allows AI models to access real-time information, use prompt templates, and interact with tools through a consistent interface. This comprehensive guide explores MCP Server architecture, authentication methods, stateful and stateless workflows, backend integrations, and best practices for building scalable AI platforms powered by connected data and intelligent automation.