Composition Root Checklist

Use this checklist when wiring a production container.

Registration

• Create typed tokens for every public dependency contract.
• Keep provider definitions close to the bootstrap/composition layer.
• Prefer useFactory for integration boundaries (db/http/queues).
• Keep domain code unaware of container APIs.

Lifecycle

• Use singleton for process-wide adapters and clients.
• Use scoped for request/job/command context.
• Use transient for stateless, short-lived objects.
• Define onInit / afterResolve only where lifecycle behavior is meaningful.

Resolution

• Use resolve() for synchronous graphs.
• Use resolveAsync() when any dependency path can be async.
• Use resolveAll() / resolveAllAsync() for multi-binding tokens.
• Use resolveOptional() only for truly optional contracts.

Safety

• Call validate() during startup.
• Wrap scope usage with try/finally and always call dispose().
• Use explain(token) for dependency troubleshooting.
• Use snapshot() for runtime introspection and monitoring.