FastMCP
Python framework for building MCP servers and clients with auth, composition, and OpenAPI generation.
About
Decorating a Python function is all it takes to expose a tool over the Model Context Protocol with FastMCP, whose 1.0 release was absorbed into the official MCP Python SDK; the actively developed v2 goes well beyond the spec basics. Servers gain authentication, server composition, and proxying, an OpenAPI or FastAPI application can be converted into an MCP server automatically, and the framework covers clients too, with in-memory testing utilities, sampling, elicitation, and a CLI for running and inspecting servers. Created by Prefect founder Jeremiah Lowin and maintained with Prefect's backing, it has become the default way Python developers build MCP integrations, reflected in roughly 27,000 GitHub stars and wide adoption across the agent ecosystem. Installation is a single pip or uv command, servers run over stdio or HTTP, and everything works offline since MCP servers need no model access of their own. The framework is Apache-2.0 licensed, with FastMCP Cloud available as a hosted deployment option forming the commercial tier.
Should you use FastMCP?
Pick it when
Choose FastMCP when you are a Python developer exposing tools, data, or an existing FastAPI or OpenAPI service to MCP clients, and need authentication, server composition, proxying, or in-memory tests beyond the protocol basics.
Look elsewhere when
Skip it if your stack is TypeScript, where the official SDK or mcp-use fits better, or if a ready-made reference server such as Filesystem, Git, or Fetch already does the job and you need no custom server code at all.
Alternatives to FastMCP
- Model Context Protocol Servers
Ready-made reference servers for files, Git, fetch, and memory that you configure instead of code, but positioned as educational, not production grade.
- mcp-use
Centered on connecting agents to MCP servers in Python, plus a TypeScript fullstack framework, a better fit when you consume servers more than build them.
- MCP Inspector
Not a framework but the official debugger; pair it with FastMCP to test tool schemas and protocol traffic rather than replacing it.
- Spring AI
Ships MCP client and server Boot starters for Java teams, the better route on the JVM, where FastMCP covers Python only.
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Details
- Category
- AI Frameworks & Libraries
- Price
- Freemium
- Platform
- Local/Desktop
- Difficulty
- Easy (2/5)
- License
- Apache-2.0
- Added
- Jul 29, 2026