Configuration

Plutonium is configured through Plutonium.configure in an initializer. A generated app has this at config/initializers/plutonium.rb:

# config/initializers/plutonium.rb
Plutonium.configure do |config|
  config.load_defaults 1.0

  # config.shell = :modern
  # config.navii_host_url = "https://api.navii.dev"

  config.assets.logo       = "plutonium.png"
  config.assets.favicon    = "plutonium.ico"
  config.assets.stylesheet = "plutonium.css"
  config.assets.script     = "plutonium.min.js"
end

Access the live config anywhere via Plutonium.configuration.

Versioned defaults

config.load_defaults 1.0

Loads the baseline defaults for a given framework version. Call this first; later versions layer their changes on top. Read the resolved version with config.defaults_version.

Options

Option	Default	Description
load_defaults(version)	—	Apply versioned framework defaults. Call first.
development	ENV["PLUTONIUM_DEV"]	Development mode for the framework itself (local assets, hot reload, verbose errors). Query with config.development?. You rarely set this in an app — see Development mode.
cache_discovery	true outside development env	Cache resource/route discovery. Disable to pick up new resources without a reboot.
enable_hotreload	true in development env	Hot-reload Plutonium components on change.
shell	:modern	Chrome style: :modern (topbar + icon rail) or :classic (legacy header + sidebar, only for upgrades). See Layouts.
navii_host_url	"https://api.navii.dev"	Host of the Navii avatar service used by Avatar. The component appends /avatar/:seed. Repoint to self-host or proxy.
assets.logo	"plutonium.png"	Brand logo asset. See Assets.
assets.favicon	"plutonium.ico"	Favicon asset.
assets.stylesheet	"plutonium.css"	Stylesheet entry.
assets.script	"plutonium.min.js"	JavaScript entry.

Development mode

config.development? is driven by the PLUTONIUM_DEV environment variable, not set in the initializer. It’s primarily for working on the Plutonium gem (uses local src/ assets, enables hot reloading, and shows more detailed errors). Applications generally leave it unset.

export PLUTONIUM_DEV=1

Assets

Asset entries live under config.assets and point the framework at your compiled stylesheet/script and brand imagery. The pu:core:assets generator wires these up. See Assets for the full asset/Tailwind/Stimulus setup.

Related

• Assets — stylesheet, script, Tailwind, and design tokens
• Layouts — the shell option and ejecting chrome
• Components › Avatar — navii_host_url