fastmcp
FastMCP, built by the team at Prefect, is a Python framework for MCP servers, clients and interactive apps. You declare a tool as an ordinary Python function and FastMCP generates the schema, validation and documentation; you connect to a server with a URL and it handles transport negotiation. FastMCP 1.0 was incorporated into the official MCP Python SDK in 2024, and the standalone project continues as the actively developed framework.
It is the natural choice for Python developers who want to expose internal APIs, databases or scripts to AI assistants, build MCP clients to test or orchestrate servers, or add interactive UIs to tools with FastMCP Apps. A TypeScript counterpart, FastMCP for TypeScript, is maintained by the same team. Documentation is extensive and also published in llms.txt format so coding agents can read it.
Getting started: add it to a project with `uv add fastmcp`, write a function decorated with `@mcp.tool`, and call `mcp.run()`. Upgrade guides cover migrations from earlier FastMCP versions and from the official SDK.
Features
Why choose it
Trade-offs
Maintenance check
- Last commit
- 2026-10-24
- Commits, last 90 days
- 100+
- Releases, last 90 days
- 28
- Latest release
- v4.1.3 (2026-10-20)
- Open issues
- 565
- Recent issues with at least one comment
- 5/19
Oldest week on the left; the latest four weeks are orange. Source: GitHub commit activity.
Status rule: archived on GitHub = Archived; last commit within 90 days = Active; 91 to 365 days = Slowing; older = Stale. All figures come from the GitHub API on the date shown.
Most discussed open issues
- #1993 FastMCP Azure Provider Auth Failed for Github Copilot in VS Code15 comments · 2025-10-03
- #4265 OAuthProxy refresh-token rotation has no grace window — duplicate/late refresh forces re-auth12 comments · 2026-06-02
- #508 Force closing a client during a tool call bricks the server12 comments · 2025-05-19
- #853 Client returns 405 method not allowed with SSE connections11 comments · 2025-06-16
- #4850 OAuthProxy: token issued by /token is immediately rejected as invalid_token at the protected endpoint10 comments · 2026-08-16
Issue titles are quoted from GitHub. Open the link to check whether a problem still applies to the version you use.
Who it fits
- You want the most productive Pythonic way to build MCP servers and clients using standard Python type hints and docstrings with minimal boilerplate.
- You want an Apache-2.0 framework maintained by Prefect that supports stdio, SSE, and Streamable HTTP transports out of the box.
- You want zero third-party wrapper layers and prefer programming directly against the reference protocol implementation; use the official MCP Python SDK.
- You already have a FastAPI web service and simply want to expose its existing routes as MCP tools; FastAPI-MCP does that automatically.
How it differs
vs python-sdk★ 24.7kFastMCP is a high-level, ergonomic framework by Prefect (Apache-2.0) that minimises boilerplate and adds client/server conveniences; the official MCP Python SDK (MIT) is the reference protocol implementation maintained by the Model Context Protocol organisation.
vs fastapi_mcp★ 12.0kFastMCP is for building purpose-designed MCP servers and clients from Python functions; FastAPI-MCP auto-generates MCP tools from an existing FastAPI application's routes.
Compatibility
Quick start
Use cases
Alternatives
Featured in these lists
Comments
No comments yet. Be the first!