FastMCP is a production-ready Python framework for building Model Context Protocol (MCP) servers and clients. It eliminates boilerplate by automatically generating schemas, validation, and documentation from Python function definitions, allowing developers to focus on business logic rather than protocol implementation. Key features of FastMCP: - Declarative server creation using Python decorators with automatic OpenAPI-compatible schema generation from type hints - Native support for MCP primitives including tools, resources, prompts, and sampling - Built-in client capabilities with automatic transport negotiation (stdio, SSE, WebSocket) and connection lifecycle management - Enterprise authentication and authorization with support for OAuth, API keys, and custom auth schemes - Composable architecture for connecting multiple servers and building complex agent workflows - Comprehensive development tools including hot reload, testing utilities, and deployment helpers Originally developed by Prefect and incorporated into the official MCP Python SDK, FastMCP serves as the foundation for the majority of MCP servers in production use across multiple languages.

FastMCP 🚀

Move fast and make things.

*Made with 💙 by Prefect*

[](https://gofastmcp.com) [](https://discord.gg/uu8dJCgttd) [](https://pypi.org/project/fastmcp) [](https://github.com/PrefectHQ/fastmcp/actions/workflows/run-tests.yml) [](https://github.com/PrefectHQ/fastmcp/blob/main/LICENSE)

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The Model Context Protocol (MCP) connects LLMs to tools and data. FastMCP gives you everything you need to go from prototype to production:

from fastmcp import FastMCP
mcp = FastMCP("Demo 🚀")
@mcp.tool
def add(a: int, b: int) -> int:
    """Add two numbers"""
    return a + b
if __name__ == "__main__":
    mcp.run()

Why FastMCP

Building an effective MCP application is harder than it looks. FastMCP handles all of it. Declare a tool with a Python function, and the schema, validation, and documentation are generated automatically. Connect to a server with a URL, and transport negotiation, authentication, and protocol lifecycle are managed for you. You focus on your logic, and the MCP part just works: with FastMCP, best practices are built in.

That's why FastMCP is the standard framework for working with MCP. FastMCP 1.0 was incorporated into the official MCP Python SDK in 2024. Today, the actively maintained standalone project is downloaded a million times a day, and some version of FastMCP powers 70% of MCP servers across all languages.

FastMCP has three pillars:

Servers

Expose tools, resources, and prompts to LLMs.

Apps

Give your tools interactive UIs rendered directly in the conversation.

Clients

Connect to any MCP server — local or remote, programmatic or CLI.

Servers wrap your Python functions into MCP-compliant tools, resources, and prompts. Clients connect to any server with full protocol support. And Apps give your tools interactive UIs rendered directly in the conversation.

Ready to build? Start with the installation guide or jump straight to the quickstart. When you're ready to deploy, Prefect Horizon offers free hosting for FastMCP users.

Installation

We recommend installing FastMCP with uv:

uv pip install fastmcp

For full installation instructions, including verification and upgrading, see the Installation Guide.

Upgrading? We have guides for:

📚 Documentation

FastMCP's complete documentation is avai