Angular is powerful, no doubt — but it’s also easy to end up with bloated apps that frustrate users and devs alike.
If your Angular project feels sluggish, you’re probably missing out on some low-hanging performance wins that could drastically improve load times, reduce memory usage, and enhance overall UX.
Let’s dive into real-world techniques to optimize your Angular apps — not just theory, but actionable insights you can apply today.
1. 📦 Use Lazy Loading (Seriously, Stop Ignoring It)
If your entire Angular app is bundled into one giant JavaScript file, users are downloading way more than they need upfront.
What to do:
Split your app into modules and load them only when needed using Angular’s built-in lazy loading feature.
const routes: Routes = [
{
path: 'admin',
loadChildren: () => import('./admin/admin.module').then(m => m.AdminModule)
}
];
✅ Faster initial load
✅ Better experience on slow networks
👉 Deep Dive into Lazy Loading Modules
2. 🧹 Remove Unused Code with Tree-Shaking
Angular uses Webpack, which supports tree-shaking — eliminating unused code during build.
But… this only works if your code is modular and avoids side-effects.
Tips:
- Use ES6 imports (
import { Something } from '...') - Avoid dynamic requires or adding properties to global objects
3. 🧠 Use OnPush Change Detection
Angular’s default change detection checks everything… every time. But most of the time, your data isn’t even changing.
Solution: Use ChangeDetectionStrategy.OnPush to update only when input-bound data changes.
@Component({
selector: 'app-optimized',
templateUrl: './optimized.component.html',
changeDetection: ChangeDetectionStrategy.OnPush
})
4. 📁 Optimize Your Bundle Size
Every KB matters.
How:
- Use
ng build --configuration productionfor AOT + optimization - Analyze with
source-map-explorer
npm install -g source-map-explorer
source-map-explorer dist/main.js
5. 🧵 Avoid Memory Leaks from Subscriptions
RxJS subscribe() is easy to use… and easy to forget to unsubscribe from.
Memory leaks lead to laggy apps that crash over time.
Use takeUntil() pattern:
private destroy$ = new Subject<void>();
ngOnDestroy() {
this.destroy$.next();
this.destroy$.complete();
}
someObservable.pipe(
takeUntil(this.destroy$)
).subscribe();
🛡️ Keep your app lean and safe
6. 📸 Use TrackBy with *ngFor for Better Rendering
Angular re-renders the entire list even if only one item changes — unless you use trackBy.
<li *ngFor="let item of items; trackBy: trackById">
{{ item.name }}
</li>
trackById(index: number, item: any): number {
return item.id;
}
⚡ Improves rendering performance significantly in large lists
7. 🧪 Enable Production Mode
In development, Angular adds extra checks and logs. You don't want that in production.
import { enableProdMode } from '@angular/core';
if (environment.production) {
enableProdMode();
}
🚀 This alone can give your app a noticeable speed boost.
8. 🧼 Debounce User Input
Forms and search boxes can easily overwhelm your app with events.
this.searchInput.valueChanges.pipe(
debounceTime(300)
).subscribe(value => {
// handle search
});
9. 🌐 Serve with HTTP/2 and Gzip
This isn't Angular-specific, but it matters:
- Enable Gzip compression
- Use HTTP/2 for multiplexing requests
Most hosting providers allow this. If you're using Firebase Hosting or Vercel, you're already good.
Otherwise, check your server config.
10. 🧠 Preload Critical Data Smartly
Don’t block your app waiting for everything.
Use Angular’s PreloadAllModules or custom preloading strategies to balance lazy loading and UX.
RouterModule.forRoot(routes, {
preloadingStrategy: PreloadAllModules
})
🔗 Guide to Preloading Strategies in Angular
🎁 Bonus: Use Angular DevTools to profile change detection cycles and performance bottlenecks in real-time.
💬 Got a performance tip you swear by? Drop it in the comments — I’d love to feature the best community suggestions in a follow-up post!
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