FastMCP

Python framework for building MCP (Model Context Protocol) servers quickly — the FastAPI equivalent for MCP, with decorators, automatic schema generation, and multi-transport support.

Evaluated Mar 06, 2026 (0d ago) v2.x

Homepage ↗ Repo ↗ Developer Tools fastmcp mcp python mcp-server tool-development model-context-protocol

⚙ Agent Friendliness

/ 100

Can an agent use this?

🔒 Security

/ 100

Is it safe for agents?

⚡ Reliability

/ 100

Does it work consistently?

Score Breakdown

⚙ Agent Friendliness

MCP Quality

Documentation

Error Messages

Auth Simplicity

Rate Limits

🔒 Security

TLS Enforcement

Auth Strength

Scope Granularity

Dep. Hygiene

Secret Handling

Apache 2.0, minimal dependency tree. Auth support added in 2.x (API key, OAuth). Tool functions run in your process — input validation via Pydantic type annotations. Self-hosted gives full control over security posture.

⚡ Reliability

Uptime/SLA

Version Stability

Breaking Changes

Error Recovery

Best When

You want to build a Python MCP server quickly — FastMCP removes the boilerplate of the official Python SDK with FastAPI-like ergonomics.

Avoid When

You need TypeScript/Node.js MCP server implementation — use the official @modelcontextprotocol/sdk instead.

Use Cases

• Building custom MCP servers to expose internal APIs or data sources to AI agents
• Rapidly prototyping agent tools with minimal boilerplate using @mcp.tool decorators
• Converting existing Python functions into MCP-compatible tools
• Creating MCP proxies that wrap and route to multiple upstream MCP servers
• Testing and developing MCP servers with built-in Claude Desktop integration

Not For

• Non-Python MCP server development (use the official TypeScript SDK for JS/TS)
• Production MCP servers requiring strict enterprise support (young project)
• Agents that consume MCP servers (this is for building servers, not clients)

Interface

REST API

GraphQL

gRPC

MCP Server

Yes ↗

SDK

Yes

Webhooks

Authentication

Methods: bearer_token

OAuth: No Scopes: No

FastMCP 2.x added authentication support via API keys or OAuth. Transport-level auth depends on chosen transport (stdio, SSE, HTTP). Proxy mode can pass-through upstream server auth.

Pricing

Model: open_source

Free tier: Yes

Requires CC: No

Fully open source and free. Infrastructure costs for hosting your MCP server are all that apply.

Agent Metadata

Pagination

none

Idempotent

Full

Retry Guidance

Documented

Known Gotchas

⚠ FastMCP 1.x vs 2.x have different APIs — 2.x is a major rewrite; don't mix docs
⚠ SSE transport requires a running HTTP server — stdio is simpler for local development
⚠ Tool function type annotations are used for schema generation — missing annotations cause poor schemas
⚠ Proxy mode (wrapping other MCP servers) is powerful but complex to configure correctly
⚠ Context parameter (for logging, progress) must be explicitly accepted in tool function signature

Alternatives

mcp-python-sdk mcp-typescript-sdk

Full Evaluation Report

Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for FastMCP.

$99

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Scores are editorial opinions as of 2026-03-06.