FastMCP is the standard Python framework for building Model Context Protocol (MCP) servers and clients. It turns ordinary Python functions into MCP tools with a single decorator and handles the protocol plumbing, transports and session management for you. FastMCP 1.0 was incorporated into the official MCP Python SDK, the team estimates the framework powers around 70% of MCP servers, and with roughly 28,000 stars on GitHub it is one of the most widely adopted pieces of infrastructure in the MCP ecosystem.
MCP is the open protocol that lets AI applications call external tools, read resources and reuse prompts. FastMCP gives Python developers a high-level, pythonic way to expose all three: decorate a function to create a tool, return data as a resource, or define a prompt template, and FastMCP generates the schemas and the server automatically. It ships with a complete client library too, so the same codebase can both serve and consume MCP servers. On top of the basics it adds authentication providers, middleware, server composition and proxying, OpenAPI integration, and deployment options ranging from a local stdio process to remote HTTP servers, which makes it suitable for quick prototypes and production tool gateways alike.
FastMCP itself is free and open source under the Apache-2.0 license. The team behind it also offers Prefect Horizon, a hosted enterprise MCP gateway with SSO, role-based access control, audit logging and a tool catalog, on paid plans, so the overall offering is best described as freemium.
FastMCP is for Python developers and platform teams building MCP servers for coding agents, chatbots and internal AI tools, and for anyone who wants a production-grade, standards-based way to connect language models to their own data and services.