FastMCP 3.0
The fast, Pythonic way to build MCP servers and clients
What is FastMCP 3.0?
How to use FastMCP 3.0?
Features
Use Cases
FAQ
Pricing
Open Source
Free
Prefect Horizon Hosting
Free
The fast, Pythonic way to build MCP servers and clients
FastMCP 3.0 is the standard Python framework for building Model Context Protocol (MCP) servers and clients. It provides a fast, Pythonic way to connect Large Language Models (LLMs) to tools and data through the MCP standard. Developed by Prefect and downloaded over a million times daily, FastMCP powers approximately 70% of MCP servers across all programming languages, making it the de facto industry standard for MCP development.
pip install fastmcp or uv add fastmcp for UV usersfrom fastmcp import FastMCPmcp = FastMCP("Your Server Name")@mcp.tool decorator on Python functionsmcp.run() or deploy it via HTTP/Prefect HorizonComponents System: Easily expose tools, resources, and prompts by wrapping Python functions with automatic schema, validation, and documentation generation Providers Architecture: Source components from anywhere including decorated functions, files on disk, OpenAPI specs, or remote servers for maximum flexibility Transforms Layer: Shape what clients see through namespacing, filtering, authorization, and versioning so the same server can present differently to different users LLM-Friendly Documentation: Access docs via MCP server endpoint, llms.txt format, or markdown for seamless AI integration Production-Ready: Built-in handling for serialization, error management, and protocol compliance following best practices Free Deployment: Deploy your FastMCP servers for free using Prefect Horizon hosting platform Active Development: Version 3.0 brings new features including Skills, Custom Providers, Tool Transformation, and Authorization systems
#1 Building AI Tool Integrations: Create custom MCP servers that expose your business logic, APIs, and databases to AI agents and LLMs for automation tasks #2 Enterprise AI Assistants: Develop production-grade MCP applications that give AI assistants access to company tools and data with proper authentication and authorization #3 AI Development Workflows: Integrate FastMCP with popular AI frameworks and SDKs to build sophisticated agentic workflows with external tool access #4 API Wrapping and Transformation: Convert existing REST APIs and OpenAPI specs into MCP-compatible servers that AI models can interact with natively #5 Multi-Tenant AI Services: Use transforms and authorization to create MCP servers that present different capabilities to different users or organizations
What is Model Context Protocol (MCP)? MCP is a standardized protocol that provides a way to connect Large Language Models to external tools and data sources. FastMCP is the leading framework for implementing MCP servers and clients in Python.
Is FastMCP free and open source? Yes, FastMCP is completely free and open source. The project is actively maintained on GitHub with over 22,000 stars and is backed by Prefect. You can also deploy your servers for free using Prefect Horizon.
What Python version does FastMCP require? FastMCP 3.0 requires Python 3.10 or higher. It is designed to be Pythonic and leverages modern Python features for clean, readable code.
How is FastMCP different from the official MCP SDK? FastMCP 1.0 was actually incorporated into the official MCP SDK in 2024. The standalone FastMCP project continues to be actively developed with additional features and is downloaded millions of times daily.
Can I use FastMCP with Claude, ChatGPT, or other AI assistants? Yes, FastMCP is designed to work with any AI system that supports the Model Context Protocol. It includes integration guides for popular AI assistants and SDKs.