Julián Pinzón Eslava pinzonjulian

The Unofficial 37signals/DHH Rails Style Guide

About This Document

This style guide was generated by Claude Code through deep analysis of the Fizzy codebase - 37signals' open-source project management tool.

Why Fizzy matters: While 37signals has long advocated for "vanilla Rails" and opinionated software design, their production codebases (Basecamp, HEY, etc.) have historically been closed source. Fizzy changes that. For the first time, developers can study a real 37signals/DHH-style Rails application - not just blog posts and conference talks, but actual production code with all its patterns, trade-offs, and deliberate omissions.

How this was created: Claude Code analyzed the entire codebase - routes, controllers, models, concerns, views, JavaScript, CSS, tests, and configuration. The goal was to extract not just what patterns are used, but why - inferring philosophy from implementation choices.

	<!DOCTYPE html>
	<html>
	<head>
	<!-- ... -->
	</head>

	<body>
	<%= if current_user.signed_in? %>
	<%= if current_page?(booking_rides_path) %>
	<% end %>

	class ExampleFormBuilder < ActionView::Helpers::FormBuilder
	def error(method, error_text = nil, options = {})
	return if errors_blank?(method) && error_text.blank?

	text = if error_text
	error_text
	elsif object.errors.custom_messages_for(method)
	object.errors.custom_messages_for(method).to_sentence
	else
	object.errors.full_messages_for(method).to_sentence

	# UNEXPECTED BEHAVIOUR

	class User < ApplicationRecord
	has_many :client_posts,
	class_name: Client::Post.name,
	foreign_key: :user_id
	end

	class Client::Post < ApplicationRecord
	# Note how the class_name is declared here

	class OrdersController < ApplicationController

	def new
	# some cool code
	end

	def create
	# some cool code
	end