Baldur

Batteries-included opinionated Rails UI engine for the importmap, Stimulus, Tailwind stack. Baldur helps Rails teams ship polished UI faster with install generators, reusable ui_* helpers, Tailwind components, and Stimulus wiring for apps using Propshaft, importmap-rails, stimulus-rails, and tailwindcss-rails.

Supported Stack

• Ruby >= 3.3
• Rails >= 7.0
• Propshaft
• importmap-rails
• stimulus-rails
• tailwindcss-rails >= 4.3.0

It ships install generators, ready ui_* helpers, Tailwind components, and Stimulus controllers so host teams can skip rebuilding common UI primitives per app.

Install

Add to your Gemfile:

gem "baldur", ">= 0.1.3"

Run:

bundle install
bundle exec rails tailwindcss:engines
bundle exec rails generate baldur:install

Rebuild Tailwind:

bundle exec rails tailwindcss:build

Optional surfaces:

bundle exec rails generate baldur:install_panel_secondary
bundle exec rails generate baldur:install_google_auth

Example

Render a sidebar with navigation and a main content area:

<%= ui_sidebar(
      brand_path: root_path,
      primary_links: [
        { name: "Dashboard", path: root_path, icon: "layout-dashboard", active: current_page?(root_path) }
      ]
    ) do |_sidebar| %>
  <main class="flex-1 p-6">
    <h1>Dashboard</h1>
  </main>
<% end %>

Getting Started

• See docs/installation.md for install steps.
• See docs/sidebar.md and docs/auth.md for common usage patterns.

Documentation

• Installation
• Styling
• Sidebar
• Auth
• Modals and Panels
• Alerts and Snackbars
• Tables
• Marketing
• Security

Security

See docs/security.md for artifact verification, MFA requirements, and vulnerability reporting.

Available Now

• [x] Host app brand theming via theme.css and config.marketing_brand
• [x] Reusable auth page shell for sign-in, sign-up, and password reset
• [x] Core UI helpers, Tailwind components, and Stimulus wiring

Roadmap

Installing

• Harden baldur:install so host assumptions are reduced
• Expand script/verify_host_install coverage
• Add end-to-end install verification in dummy app

Showcase

• Add a dedicated dummy app for visual smoke checks
• Add component inventory/showcase page in dummy app
• Add interaction showcase pages for modal, sidebar, menu select, snackbar, and panel_secondary
• Add copy-paste examples for core surfaces from the showcase app back into docs

Starter Templates

• Add dedicated password reset templates
• Add magic link templates
• Add error/system pages
• Add starter settings page layout
• Add starter CRUD index/show/form templates
• Add starter dashboard shell/page templates

Forms

• Add Rails form-builder integration for Baldur fields
• Bind labels, hints, errors, and invalid states automatically
• Document model-bound form usage

Tables and Resource Screens

• Add a higher-level resource index pattern on top of existing table primitives
• Support search, filters, row actions, bulk select, and empty states
• Document recommended resource index composition

Theming

• Add a small set of starter theme presets
• Improve dark-mode/theme controller documentation
• Document brand-token customization more clearly

Accessibility

• Audit keyboard and focus behavior across interactive components
• Add accessibility-focused tests for core surfaces
• Document a11y guarantees and known gaps

Internationalization

• Add I18n-friendly labels/messages for reusable helpers
• Remove hard-coded helper copy where practical
• Document translation override points

Contributing

Open an issue or PR. Before you start, read CONTRIBUTING.md and docs/security.md.

Changelog

See CHANGELOG.md.

License

MIT. See LICENSE.