Python

A decorator, 3 imports,
and a runtime you didn't ask for.

zeromcp vs FastMCP — side by side.

Dependencies

0 ZeroMCP

vs.

37 Official SDK

Throughput

2,623 req/s

vs.

635 req/s

Memory

27 MB

vs.

87 MB

This is a hello world

A decorator, a server class, and a run call. The official SDK wraps everything in ceremony before your tool does anything.

FastMCP 8 lines

from mcp.server.fastmcp import FastMCP

mcp = FastMCP("test")

@mcp.tool()
def hello(name: str) -> str:
    return f"Hello, {name}!"

mcp.run()

This is the whole server

No decorator. No server class. No run call.
Drop it in a folder and run zeromcp serve.

ZeroMCP 7 lines

# tools/hello.py
tool = {
    "description": "Say hello",
    "input": {"name": "string"},
}

async def execute(args, ctx):
    return f"Hello, {args['name']}!"

HTTP Performance — Head to Head

Same hello tool. Same methodology. 5-minute sustained load in Docker. Starlette for ZeroMCP, stdio proxy for the official SDK.

ZeroMCP (Starlette) 2,623 0.28% 27 MB 4.1x

Official SDK 635 0.04% 87 MB

ZeroMCP HTTP Frameworks

ZeroMCP embedded natively in Python frameworks. No proxy. No subprocess. 30-second sustained load.

FastAPI 4,592 0.46ms — 45 MB

Flask 2,006 1.30ms — 34 MB

What's different

SandboxEnforced. Not advisory.
CredentialsPer-directory. Not os.environ.
ProcessesOne. Not N.
Hot reloadBuilt-in. Not restart.
ComposabilityConnect remote MCP servers. Official SDK can't.
TransportStreamable HTTP by default. Stdio too.

When to use the official SDK

ZeroMCP makes trade-offs. Here's what you give up.

Resources and prompts

ZeroMCP implements tools only. If you need MCP resources, prompts, or sampling, use the official SDK.

Type hints

ZeroMCP uses a simplified input dict. If your team uses Pydantic for validation, the official SDK integrates it via FastMCP.

Spec parity

The official SDK tracks every spec change immediately. ZeroMCP prioritizes stability over spec completeness.

Enterprise support

The official SDK is maintained by the MCP specification team at Anthropic. ZeroMCP is maintained by the antidrift team (Reloop Labs, LLC).

Drop a .py file. It's an MCP tool.

Get started See all benchmarks →

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A decorator, 3 imports,and a runtime you didn't ask for.