App Properties

The $app.* namespace exposes platform-injected properties of the deployed app itself. These are resolved at deploy time by whichever provider is running the app, so a Launchfile can reference its own public URL without hardcoding environment-specific values.

Property	Description
`$app.url`	The app's public URL (e.g. `https://myapp.example.com`)
`$app.host`	The app's public hostname (e.g. `myapp.example.com`)
`$app.port`	The app's allocated public port number
`$app.name`	The app name as deployed
`$app.authority`	The app's public host and port, port omitted when it's the default for the scheme (e.g. `myapp.example.com` or `myapp.lvh.me:10001`)
`$app.scheme`	The public URL's scheme — `http` or `https`
`$app.tls`	Whether the public URL is HTTPS — the string `true` or `false`

The values are determined by the provider's routing strategy at deploy time. A Cloudflare Tunnel deployment might resolve $app.url to https://myapp.example.com; a local development provider might resolve it to http://myapp.lvh.me:10001; a Kubernetes deployment behind an Ingress might resolve it to https://myapp.k8s.internal. The Launchfile stays the same.

The standard set above is the portable vocabulary every provider must support. Providers MAY expose additional $app.* properties (e.g. $app.region, $app.deployment_id) as platform-specific extensions; portable Launchfiles should use only the standard set. Unknown $app.* properties resolve to empty string, matching the behavior of unknown resource properties (see L-4).

$app.url differs from $components.<this>.url in two ways. First, it gives the public URL — the address external users reach the app on — not the internal component port. Second, it works in single-component mode where there is no component name to reference. Use $app.url for public-facing values (auth callback URLs, webhook registration, public-facing email links) and $components.<name>.url for internal cross-component wiring.

Similarly, $app.port is the allocated external port that the platform exposes; provides[].port is the container port the component binds inside its sandbox. They can differ — a component might bind 3000 while the platform exposes 10001.

$app.authority, $app.scheme, and $app.tls are derived directly from $app.url, so a provider that can resolve the URL can resolve all three. $app.authority is the WHATWG URL host — the hostname plus the port, with the port omitted when it is the default for the scheme (:443 under https, :80 under http). $app.scheme is the URL scheme (http or https); $app.tls is the boolean form of that scheme (true when https, else false), provided for apps whose config expects a literal SSL on/off flag rather than a scheme string. Prefer $app.url for the single-string case; reach for these three only when an app needs the public address split into its component fields.

Example use:

env:
  PUBLIC_URL: $app.url                # Drupal, BookStack, Mealie, Firefly III
  BETTER_AUTH_URL: $app.url           # better-auth callback base
  OAUTH_REDIRECT_URI: "${app.url}/oauth/callback"
  WEBHOOK_URL: "${app.url}/webhooks/incoming"

  # Apps that need the public address split into separate fields (HedgeDoc):
  CMD_DOMAIN: $app.authority          # public host[:port] HedgeDoc serves from
  CMD_PROTOCOL_USESSL: $app.tls       # whether the public URL is HTTPS
  CMD_URL_ADDPORT: "false"            # authority already carries the public port