Ruby

Drop a .rb file.
517 lines. No gems.

zeromcp vs mcp gem — side by side.

Tested April 7, 2026 · zeromcp-benchmarks v1.0 · Reviewed by ZeroMCP Team

Dependencies

0 ZeroMCP

vs.

90 Official SDK

Throughput

4.26K req/s ZeroMCP

vs.

2.16K req/s Official SDK

Memory

26 MB ZeroMCP

vs.

56 MB Official SDK

This is a hello world

Require, server instantiation, class-based registration, schema definition, and transport setup. 12 lines before your tool does anything.

mcp gem 12 lines

require 'mcp'

server = MCP::Server.new(
  name: "test", version: "1.0.0")
server.register_tool("hello",
  description: "Say hello",
  input_schema: {
    name: { type: "string" }
  }) do |args|
  "Hello, #{args['name']}!"
end
server.run_stdio

This is the whole server

No require. No server class. No registration blocks.
Drop it in a folder and run zeromcp serve.

ZeroMCP 8 lines

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

def execute(args, ctx)
  "Hello, #{args['name']}!"
end

HTTP Performance — Head to Head

Mixed workload across all 7 MCP method types. 5-minute sustained load in Docker. Rack+Puma for ZeroMCP, stdio proxy for the official SDK.

ZeroMCP (Rack+Puma) 4.26K 0.06% 26 MB 2.0x

Official SDK 2.16K 0.04% 56 MB

The tradeoff

Choose the mcp gem

If you want the canonical Ruby MCP interface and are willing to work through the documentation gaps.

Block DSL — registration pattern familiar to Ruby devs
Spec parity — tracks every spec change immediately
Enterprise support — maintained by the MCP specification team at Anthropic

Choose ZeroMCP

If you want it working on the first try. Drop a .rb file, zero gems, 517 lines.

0 gems
File-based tools — drop a .rb file, it's live
Rack+Puma + Sinatra
Built-in sandbox with enforced permissions
4.26K req/s on Rack+Puma

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

Get started All comparisons → See all benchmarks →

Other languages

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Drop a .rb file.517 lines. No gems.