This document is an unofficial Rails style guide distilled from the Fizzy codebase, a real-world 37signals/DHH Rails application.

It defines a philosophy of **“vanilla Rails is plenty”**: rich domain models instead of service objects, CRUD-oriented controllers and routes, concerns for horizontal sharing, and database-backed infrastructure without Redis. It catalogs concrete patterns and anti-patterns across routing, controllers, models, views, jobs, testing, naming, caching, multi-tenancy, Stimulus/Hotwire, and gem choices, emphasizing minimal dependencies and custom implementations over popular libraries like Devise, Pundit, Sidekiq, Redis, and GraphQL.