Bootstrap Options

bootstrap() accepts an optional BootstrapOptions object. All fields are optional.

await MY_APP.bootstrap({
  configuration: { boilerplate: { LOG_LEVEL: "debug" } },
  bootLibrariesFirst: true,
  loggerOptions: { mergeData: { env: "production" } },
});

Options reference

Field	Type	Default	Description
configuration	PartialConfiguration	—	Override config values at highest priority
bootLibrariesFirst	boolean	false	Boot libraries through Bootstrap before wiring app services
appendLibrary	TLibrary | TLibrary[]	—	Add extra libraries after construction
appendService	ServiceMap	—	Add extra services to the application
loggerOptions	LoggerOptions	—	Fine-tune the built-in logger
customLogger	GetLogger	—	Replace the built-in logger entirely
handleGlobalErrors	boolean	true	Catch uncaught exceptions and unhandled rejections
showExtraBootStats	boolean	false	Print per-service construction times after boot
envFile	string	".env"	Path to .env file for config sourcing
configSources	Partial<Record<DataTypes, boolean>>	all true	Enable/disable specific config loaders

configuration

Provides config values at the highest priority — overrides env, argv, and file sources. Uses the same PartialConfiguration type as .configure() in TestRunner.

await MY_APP.bootstrap({
  configuration: {
    boilerplate: { LOG_LEVEL: "warn" },
    my_app: { DATABASE_URL: "postgres://localhost/mydb", PORT: 5432 },
  },
});

bootLibrariesFirst

By default, all services (library and application) are wired first, then lifecycle stages run for everything together. With bootLibrariesFirst: true, the sequence changes:

Use bootLibrariesFirst: true when application services need library resources (a database connection, a cache client) to be fully established before their own service function body runs — not just before a lifecycle callback.

appendLibrary / appendService

Adds libraries or services that weren't declared in the original CreateApplication call. Useful for test helpers, plugins, or runtime-determined extensions. If a name collides with an existing library or service, the appended version takes priority.

loggerOptions

Fine-tune the built-in logger without replacing it. See Project Tuning for all LoggerOptions fields.

loggerOptions: {
  mergeData: { env: process.env.NODE_ENV, host: hostname() },
  ms: true,
  counter: false,
}

customLogger

Replace the built-in logger with your own implementation. Must implement the GetLogger interface. Useful for integrating with external logging systems (Datadog, OpenTelemetry).

configSources

Disable specific config loaders. By default all sources are enabled. Setting a source to false prevents that loader from running.

configSources: {
  env: false,  // ignore environment variables
  argv: false, // ignore command-line arguments
}

Process exit codes

The framework registers SIGTERM and SIGINT handlers automatically. On signal receipt, it runs the full shutdown sequence then exits with the appropriate code:

Event	Exit code
Bootstrap error	1 (EXIT_ERROR)
SIGINT (Ctrl+C)	130
SIGTERM	143

Normal application exit (all lifecycle callbacks complete without error) does not call process.exit() — the Node.js process exits naturally.

Common errors

Error cause	What it means
DOUBLE_BOOT	bootstrap() called on an already-running application
BAD_SORT	Circular dependency between libraries
MISSING_DEPENDENCY	A library's depends entry is not in the app's libraries array
REQUIRED_CONFIGURATION_MISSING	A required: true config entry has no value at PostConfig
MISSING_PRIORITY_SERVICE	A name in priorityInit doesn't exist in services