Angular 21 — What’s New, What’s Changed

Angular 21 focuses on simplification, performance, and modern reactive patterns. Instead of adding flashy APIs, it strengthens what Angular developers already use daily.

Let’s explore Angular 21 features with practical examples so you can immediately apply them.

1. Standalone Components by Default (No NgModules)

❌ Old Way (NgModule-based)

@NgModule({
  declarations: [UserComponent],
  imports: [CommonModule],
})
export class UserModule {}

✅ Angular 21 Way (Standalone)

@Component({
  selector: 'app-user',
  standalone: true,
  imports: [CommonModule],
  template: `<h2>User Works!</h2>`
})
export class UserComponent {}

✅ Benefits

• Less boilerplate
• Clear dependencies
• Easier lazy loading

2. Signals for State Management (Simple & Predictable)

❌ Before (RxJS for simple state)

user$ = new BehaviorSubject<User | null>(null);

✅ Angular 21 Signals

user = signal<User | null>(null);

setUser(data: User) {
  this.user.set(data);
}

Using it in template:

<div *ngIf="user()">
  Welcome {{ user()?.name }}
</div>

➡️ No subscriptions. No memory leaks. Clean reactivity.

3. Computed Signals (Derived State)

firstName = signal('Mridu');
lastName = signal('Dixit');

fullName = computed(() => `${this.firstName()} ${this.lastName()}`);

<h3>{{ fullName() }}</h3>

➡️ Angular automatically recalculates when dependencies change.

4. Effect API (Reacting to Changes)

effect(() => {
  console.log('User changed:', this.user());
});

Use cases:

• Analytics tracking
• API calls
• Logging
• Syncing localStorage

5. Zoneless Angular (Better Performance)

Angular 21 makes Zone.js optional.

Enable zoneless mode:

bootstrapApplication(AppComponent, {
  providers: [provideZoneChangeDetection({ eventCoalescing: true })]
});

Result:

• Faster change detection
• More predictable updates
• Signals + zoneless = 🔥

6. Faster Builds with esbuild (Under the Hood)

You don’t configure this manually — Angular CLI handles it.

What you’ll notice:

• Faster ng serve
• Faster rebuilds
• Lower memory usage

Especially noticeable in large projects.

7. Improved SSR & Hydration (Less Pain)

Server Component Example:

@Component({
  standalone: true,
  template: `<p>Data loaded on server</p>`
})
export class ServerOnlyComponent {}

Angular 21 improves:

• Hydration mismatch handling
• Async data consistency
• Debugging experience

Result → more reliable SSR apps.

8. Better Dependency Injection with Standalone Apps

Global provider:

bootstrapApplication(AppComponent, {
  providers: [provideHttpClient()]
});

Component-level provider:

@Component({
  standalone: true,
  providers: [UserService]
})
export class UserComponent {}

➡️ Clear scope, fewer surprises.

9. Stronger Template Type Safety

Angular catches this at build time:

<p>{{ user.nonExistingProp }}</p>

✔ No more silent runtime bugs
✔ Better IDE autocomplete
✔ Safer refactors

10. Migration Is Smooth (No Breaking Shock)

Angular 21 supports:

• Existing RxJS code
• NgModules (still supported)
• Incremental migration to signals

You don’t have to rewrite everything.

Who Should Use Angular 21?

✅ New Angular projects
✅ Apps already using standalone components
✅ Performance-sensitive apps
✅ Teams tired of overusing RxJS for simple state

Final Thoughts

Angular 21 is about clarity and confidence:

• Standalone-first architecture
• Signals for state
• Zoneless performance
• Faster builds
• Cleaner mental model

Angular is no longer “heavy” — it’s modern, reactive, and production-ready.