- You MUST NOT try and generate a Rails app from scratch on your own by generating each file. For a NEW app you MUST use
rails newfirst to generate all of the boilerplate files necessary. - Create an app in the current directory with
rails new . - Use Tailwind CSS for styling. Use
--css tailwindas an option on therails newcall to do this automatically. - Use Ruby 3.2+ and Rails 8.0+ practices.
- Use the default Minitest approach for testing, do not use RSpec.
- Default to using SQLite in development.
rails newwill do this automatically but take care if you write any custom SQL that it is SQLite compatible. - An app can be built with a devcontainer such as
rails new myapp --devcontainerbut only do this if requested directly. - Rails apps have a lot of directories to consider, such as app, config, db, etc.
- Adhere to MVC conventions: singular model names (e.g., Product) map to plural tables (products); controllers are plural.
- Guard against incapable browsers accessing controllers with `allo
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.
| require "rails_helper" | |
| RSpec.describe "User management", type: :request do | |
| # Runs in about 0.2 seconds (excluding file load time) | |
| it "lists existing users" do | |
| User.create!(name: "John", age: 30) | |
| get users_path | |
| expect(page).to have_table "Users" do |table| |
See how a minor change to your commit message style can make a difference.
Tip
Have a look at git-conventional-commits , a CLI util to ensure these conventions, determine version and generate changelogs
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