If you're building an MCP server in Python, you pick between two projects with a tangled history: FastMCP, the decorator-first framework, and the official modelcontextprotocol/python-sdk. They were once the same code and have since split hard. Here's what actually differs in 2026, and which to reach for.
The shared history
FastMCP 1.0 was folded into the official Python SDK back in 2024 — which is why the SDK's high-level class was literally called FastMCP. The projects then diverged. The standalone FastMCP, by Jeremiah Lowin and now maintained under PrefectHQ, reached a stable 3.0 on 18 February 2026. On 30 June 2026 the official SDK shipped a v2.0 beta that renames its bundled class from FastMCP to MCPServer.
Ergonomics
Both wrap tools in decorators, but the balance differs. FastMCP leans into ergonomics — less boilerplate, more batteries included. The official SDK gives you rawer spec control at the cost of writing more yourself. For a first server, FastMCP is the gentler on-ramp:
pip install fastmcp
Advanced features
FastMCP 3.x is where the extras live: compose multiple servers into one, proxy a third-party server to add auth or new features, and auto-generate tools from an existing REST API. If your plan is "wrap our API as an MCP server," that proxy and generation story is often the deciding factor on its own.
Which to pick
Building something standard and want the broadest, most active framework? FastMCP. Want to track the reference implementation exactly, or contribute upstream? The official SDK — but note its v1.x is in maintenance mode and the v2.0 beta stays pre-release until the 28 July 2026 spec date, so pin an exact version in production for now and add an upper bound.
Going further
Ready to build? Follow the Python MCP tutorial or the Node.js version. Compare transports in Streamable HTTP vs SSE vs stdio, then publish your server to the registry and secure it with the OAuth 2.1 guide.