Develop Robust Ruby on Rails Applications

This is a coding-standards skill for Ruby on Rails development, opinionated toward Rails 8's server-rendered-first stack: Hotwire (Turbo and Stimulus) over custom JavaScript, SQLite3 as the preferred database, SolidQueue for background jobs (explicitly instead of Sidekiq or Redis), SolidCable for WebSockets, and SolidCache for caching frequently accessed views or partials. It directs long-running tasks - the example given is syncing with the Stripe API - into background queues rather than the request cycle. Beyond stack choice, it codifies Rails-idiomatic code style: snake_case for files, methods, and variables; CamelCase for classes and modules; descriptive method names like user_signed_in? and calculate_total; Ruby 3.x features such as pattern matching and endless methods; and Ruby's expressive syntax (unless, ||=, &.) with single quotes unless interpolation is needed.

Use this skill when building or reviewing a Ruby on Rails 8 application that follows the modern "Solid" stack (SolidQueue, SolidCable, SolidCache) instead of the traditional Sidekiq/Redis/ActionCable combination, and wants Hotwire-first interactivity rather than a separate JS framework. It explicitly steers away from Sidekiq and Redis for queues, so it isn't the right fit for a codebase already committed to that stack, or for a project that needs a heavier client-side JavaScript framework rather than Turbo and Stimulus.

Inputs are Rails code under review or being written - models, controllers, views, background jobs - evaluated against explicit conventions: RESTful routing, concerns for shared behavior across models or controllers, service objects for complex business logic, and background jobs for anything time-consuming. Output is Rails code and review guidance covering error handling (exceptions for exceptional cases only, ActiveModel validations, user-friendly flash messages), performance (database indexing, fragment and Russian Doll caching, eager loading via includes/joins/select to avoid N+1 queries), and security (generating authentication with rails g authentication, strong parameters, and protection against XSS, CSRF, and SQL injection).

Built around Rails 8's own "Solid" gems - SolidQueue, SolidCable, SolidCache - plus Hotwire (Turbo and Stimulus), Tailwind CSS, ActiveRecord, and ActiveModel; follows the official Ruby Style Guide for syntax conventions. On the UI side it calls for using Rails view helpers and partials to keep views DRY rather than duplicating markup, alongside Hotwire for the dynamic, SPA-like interactions and Tailwind for responsive layout - so the interactivity layer and the view-organization layer are treated as separate, equally-enforced concerns rather than left to individual preference.

Rails developers building on Rails 8's Solid-stack defaults with Hotwire and Tailwind CSS, who want code style, naming, performance, and security conventions enforced consistently rather than decided ad hoc per file.