Suggest an editImprove this articleRefine the answer for “What is the root injector (root injector)?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**Root injector** is the main injector for the entire Angular application, created when the app starts and living for as long as it runs. **Key point:** The root injector holds every service registered with `providedIn: 'root'`, and each one exists as a singleton across the whole application.Shown above the full answer for quick recall.Answer (EN)Image**Root injector** is the **main injector for the entire Angular application**. It is created when the application starts and lives for as long as the application runs. --- ### What it does: - stores **all dependencies marked with** `providedIn: 'root'`; - creates services once and **shares them across the whole application**; - manages the lifetime of these services (singleton, a single instance). --- ### Example: ```ts @Injectable({ providedIn: 'root' }) export class UserService {} ``` Angular registers `UserService` in the **root injector**, and now this service is available in any component without being created again. --- ### Why it is needed: - so services are **shared across all parts of the application**; - to avoid duplication and save memory; - to manage dependencies centrally. --- **Summary:** The root injector is Angular's main dependency "container", from which all of the application's global services are drawn.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.