What is Angular Standalone API?

The Standalone API (Angular 14+, stable Angular 15+) is a major simplification of Angular's architecture, reducing boilerplate by eliminating the requirement for NgModules. Standalone components: @Component({ standalone: true, selector: "app-user-card", template: "...", imports: [CommonModule, RouterModule, MatButtonModule] }). The standalone: true flag makes the component self-contained — it declares its own imports directly. Bootstrapping a standalone app: no AppModule — use bootstrapApplication in main.ts: bootstrapApplication(AppComponent, { providers: [ provideRouter(routes), provideHttpClient(withInterceptorsFromDi()), importProvidersFrom(MatDialogModule), { provide: HTTP_INTERCEPTORS, useClass: AuthInterceptor, multi: true } ] });. Standalone directives and pipes: @Directive({ standalone: true, selector: "[appHighlight]" }). Lazy loading standalone components: { path: "profile", loadComponent: () => import("./profile.component").then(m => m.ProfileComponent) }. Benefits over NgModules: (1) Less boilerplate (no declarations/exports arrays); (2) Explicit dependencies (each component declares exactly what it uses); (3) Better tree-shaking; (4) Easier testing (no TestBed.configureTestingModule module setup); (5) Simpler mental model. Interoperability: standalone components can be used inside NgModule-based apps and vice versa. Migration: ng generate @angular/core:standalone schematics automate migration from NgModule-based to standalone. Angular 17 defaults to standalone for new projects.