rails-metro

The ultimate Rails app scaffolding tool. Pick the features you need -- authentication, analytics, payments, background jobs, and 120+ more -- and get a production-ready Rails app in one command.

rails-metro compiles your selections into a Rails Application Template, runs rails new, and hands you a standard Rails app with no runtime dependency on this gem.

RubyGems

gem install rails-metro

# For the interactive TUI (optional)
gem install bubbletea

Homebrew

brew tap rish/tap
brew install metro

Arch Linux (AUR)

yay -S ruby-rails-metro

# Interactive mode (recommended)
metro tui

# CLI mode
metro new myapp --packs=authentication,posthog,background_jobs,deployment --database=postgresql

# Just generate the template file
metro template myapp --packs=posthog,blazer --output=template.rb

# Generate from a saved config
metro from_config metro.yml

metro new myapp \
  --database=postgresql \        # sqlite3, postgresql, mysql2
  --packs=auth,posthog,deploy \  # comma-separated pack names
  --rails_args="--api"           # pass-through to rails new

The TUI walks you through four steps:

1. App name -- validates format
2. Database -- sqlite3, postgresql, or mysql2
3. Pack selection -- browse by category, search with /, toggle with Space
4. Review -- generate the app, export config, or export template

Dependencies are auto-resolved and conflicts are blocked inline.

Requires the bubbletea gem (gem install bubbletea).

• activeadmin -- ActiveAdmin -- classic, battle-tested admin framework
• administrate -- Administrate -- Thoughtbot's lightweight admin framework
• avo -- Avo -- modern, customizable admin panel framework
• madmin -- Madmin -- a modern admin framework by Chris Oliver (GoRails)

• ahoy -- Ahoy for visit and event tracking (first-party analytics)
• amplitude -- Amplitude for product analytics, funnels, and retention
• blazer -- SQL analytics dashboards with Blazer
• clicky -- Clicky for real-time web analytics
• fathom -- Fathom -- simple, privacy-focused website analytics
• google_analytics -- Google Analytics 4 (GA4) for web analytics
• google_tag_manager -- Google Tag Manager for managing analytics and marketing tags
• heap -- Heap for auto-captured product analytics
• matomo -- Matomo -- self-hosted open-source web analytics
• mixpanel -- Mixpanel for event-based product analytics
• plausible -- Plausible -- privacy-focused analytics (no cookies, GDPR compliant)
• posthog -- PostHog product analytics (server-side + JS snippet)
• statcounter -- StatCounter for visitor stats and web analytics

• api_cors -- Rack CORS for cross-origin API requests
• api_docs -- Rswag for Swagger/OpenAPI documentation from tests
• api_guard -- API Guard for JWT authentication
• api_serialization -- Alba for fast, flexible JSON serialization
• doorkeeper -- Doorkeeper for OAuth2 provider
• graphql -- GraphQL API with graphql-ruby
• webhooks -- Incoming and outgoing webhook handling

• authentication -- authentication-zero (2FA, recovery codes, you own the code)
• authorization -- Action Policy for authorization
• background_jobs -- Solid Queue + Mission Control Jobs (no Redis)
• caching -- Solid Cache (database-backed caching)
• devise -- Devise for full-featured authentication
• faraday -- Faraday for composable HTTP requests
• good_job -- GoodJob for Postgres-backed background jobs
• invisible_captcha -- Invisible Captcha for honeypot spam prevention
• mobility -- Mobility for translatable model attributes
• multitenancy -- acts_as_tenant for row-based multi-tenancy
• omniauth -- OmniAuth for social/OAuth login
• passwordless -- Passwordless for magic-link authentication
• pundit -- Pundit for simple, policy-based authorization
• r2_storage -- Cloudflare R2 for Active Storage (no egress fees)
• rails_i18n -- Rails I18n locale data for 100+ languages
• recaptcha -- reCAPTCHA v3 for bot protection
• rolify -- Rolify for role management
• s3_storage -- AWS S3 for Active Storage
• scheduling -- Recurring tasks with Solid Queue (requires: background_jobs)
• sidekiq -- Sidekiq for Redis-backed background jobs
• websockets -- Solid Cable (database-backed ActionCable)

• aasm -- AASM for state machines
• ab_testing -- Split for A/B testing
• activity_feed -- Public Activity for timelines
• acts_as_list -- Acts As List for sortable records
• acts_as_votable -- Acts As Votable for likes/upvotes
• annotate -- Annotate models with schema info
• audit_trail -- PaperTrail for model versioning
• counter_culture -- Counter Culture for counter caches
• data_migrate -- Data Migrate for data migrations
• elasticsearch -- Searchkick for Elasticsearch search
• encryption -- Lockbox for field encryption
• event_sourcing -- Rails Event Store for event sourcing/CQRS
• geocoder -- Geocoder for address lookup and distance
• kredis -- Kredis for structured Redis types
• meilisearch -- Meilisearch for fast full-text search
• scenic -- Scenic for versioned database views
• search -- pg_search for PostgreSQL full-text search
• soft_deletes -- Discard for soft deletes
• storage_validations -- Active Storage file validations
• strong_migrations -- Catch unsafe migrations before they run
• tagging -- Acts As Taggable On

• aws_ses -- Amazon SES for email delivery
• mailgun -- Mailgun for transactional email
• notifications -- Noticed for multi-channel notifications
• postmark -- Postmark for transactional email
• resend -- Resend for email delivery
• sendgrid -- SendGrid for email delivery
• sent_dm -- Sent.dm for multi-channel messaging
• slack_notifier -- Slack webhook notifications
• twilio -- Twilio for SMS, voice, and WhatsApp
• web_push -- Web Push for browser notifications

• after_party -- AfterParty for one-time post-deploy tasks
• app_linting -- Standard Ruby + ERB Lint
• circuit_breaker -- Circuitbox for circuit breaking
• datadog -- Datadog APM for tracing and metrics
• deployment -- Kamal for zero-downtime deploys
• dotenv -- Dotenv for .env files in development
• error_tracking -- Sentry for error tracking
• feature_flags -- Flipper for feature flags
• health_check -- OkComputer for health check endpoints
• honeybadger -- Honeybadger for error tracking
• hotwire_livereload -- Hotwire LiveReload for dev
• letter_opener -- Letter Opener for email preview (dev)
• letter_opener_web -- Letter Opener Web UI (requires: letter_opener)
• logging -- Lograge for structured request logs
• maintenance_mode -- Turnout for maintenance pages
• maintenance_tasks -- Maintenance Tasks (Shopify)
• newrelic -- New Relic APM
• performance -- Rack Mini Profiler + Bullet
• pghero -- PgHero for Postgres performance dashboard
• pretender -- Pretender for user impersonation
• profiling -- Stackprof + memory_profiler
• rack_timeout -- Rack::Timeout for request protection
• rate_limiting -- Rack::Attack for throttling
• rollbar -- Rollbar for error tracking
• security -- Brakeman + bundler-audit

• lemon_squeezy -- Lemon Squeezy (merchant of record)
• mollie -- Mollie for European payments
• paddle -- Paddle (merchant of record)
• payments -- Pay + Stripe for subscriptions
• paypal -- PayPal for payments and checkout
• revenuecat -- RevenueCat for subscription management
• solidus -- Solidus for full e-commerce

• seo -- meta-tags + sitemap_generator

• shoulda_matchers -- Shoulda Matchers for one-liner assertions
• simplecov -- SimpleCov for code coverage
• test_mocking -- VCR + WebMock for HTTP recording
• testing -- FactoryBot + Faker + Capybara

• action_text -- Action Text for rich text editing
• breadcrumbs -- Gretel for breadcrumb navigation
• charting -- Chartkick + Groupdate for charts
• cloudinary -- Cloudinary for image/video management
• components -- ViewComponent for component-based views
• friendly_id -- FriendlyId for URL slugs
• icons -- Lucide Rails for SVG icons
• markdown -- Redcarpet for Markdown rendering
• pagination -- Pagy for pagination
• pdf -- Grover for PDF generation
• qr_code -- RQRCode for QR code generation
• ransack -- Ransack for search/filter forms
• simple_calendar -- Simple Calendar for calendar views
• simple_form -- Simple Form for form building
• spreadsheets -- Caxlsx for Excel generation
• stimulus_components -- Pre-built Stimulus controllers
• vite_rails -- Vite Rails for frontend bundling with HMR

Packs can declare dependencies and conflicts:

• Dependencies are auto-resolved. Selecting scheduling automatically adds background_jobs.
• Conflicts are mutually exclusive. You can't select both authentication and devise, or both sidekiq and good_job.

1. You select packs via the TUI, CLI flags, or a metro.yml config file
2. rails-metro resolves dependencies and validates conflicts
3. A Rails Application Template is compiled from your selections
4. rails new runs with that template
5. You get a standard Rails app -- no runtime dependency on rails-metro

Export and reuse configurations:

# metro.yml
app_name: myapp
database: postgresql
selected_packs:
  - authentication
  - posthog
  - background_jobs
  - deployment
rails_args: ""

metro from_config metro.yml

bundle install
bundle exec rake test          # Unit + golden file tests
bundle exec rake test:tui      # TUI step tests
bundle exec rake test:integration  # End-to-end (runs rails new)
bundle exec rake test:all      # Everything
bundle exec rake standard      # Lint

MIT