Backend5 min read

Ruby on Rails

Build web applications with Rails - ActiveRecord patterns, generators, Hotwire for modern UIs, background jobs with Sidekiq, and Rails conventions.

RubyRailsActiveRecordMVCConvention over Configuration

skill: Ruby on Rails category: Backend tags: [Ruby, Rails, ActiveRecord, MVC, Convention over Configuration] readingTime: 5

Rails is the original convention-over-configuration framework - it makes CRUD applications the fastest to build by eliminating decisions through opinionated defaults. For teams that fit its conventions, Rails remains one of the most productive frameworks. The pitfall: straying too far from the conventions erodes the productivity benefit.

Workflow

Use ActiveRecord effectivelyActiveRecord is Rails' ORM - its conventions (table names from class names, primary keys as "id") reduce boilerplate. But N+1 queries and missing indexes are common pitfalls.
Generate and migrate with Rails generatorsRails generators create models, controllers, migrations, and tests in seconds. They enforce conventions and wire all pieces together automatically.
Build modern UIs with HotwireHotwire (Turbo + Stimulus) delivers SPA-like UX without writing JavaScript frameworks. Server renders HTML; Turbo updates the page; Stimulus handles JavaScript behavior.
Run background jobs with SidekiqLong-running tasks (emails, image processing, API calls) should not run in the web request cycle. Sidekiq processes them asynchronously using Redis.
Cache effectively in RailsRails caching reduces database queries and improves response times. Fragment caching, low-level caching, and HTTP caching all have their place.

Output Format

Rails: ActiveRecord with includes for N+1 prevention, generators for scaffolding, Hotwire Turbo Frames for partial page updates, Sidekiq for async jobs, and fragment + low-level caching.

ActiveRecord: User.includes(:orders).where(active: true)
Migration: create_table + add_index
Hotwire: <turbo-frame id="user_N"> for partial updates
Sidekiq: perform_later(id) + retry_on + queue_as
Cache: Rails.cache.fetch("key", expires_in: 5.minutes) { query }

Examples

Input

Output

Edge Cases & Gotchas

Callbacks and service objects - Rails after_create, before_save callbacks make models hard to test and reason about. Extract complex logic into service objects or form objects rather than piling it into model callbacks.
Database connection pool - Each Rails web worker needs its own DB connection. With 3 Puma workers × 5 threads = 15 connections needed. Set pool: 15 in database.yml or use PgBouncer.
Sidekiq job idempotency - Sidekiq at-least-once delivery means jobs may run multiple times (worker crash). Jobs must be idempotent. Use find_or_create_by instead of create, and check before sending emails.
Asset pipeline vs. Vite - Rails 7+ ships with import maps (no bundler) or jsbundling-rails (webpack/esbuild/Vite). For React/Vue-heavy apps, use vite-rails for the best DX.

When to Break These Rules

Use Next.js or Nuxt instead of Rails when your team is JavaScript-first and building a heavily client-side application - Rails views add friction when the frontend is a separate SPA.
Use FastAPI or Express when you need to expose a pure API (no server-rendered HTML) - Rails's full stack is overkill for API-only services.

Reference Files

https://guides.rubyonrails.org/
https://hotwired.dev/