DEV Community: Alejandro

Angular performance optimization: change detection mistakes you should avoid

Alejandro — Fri, 03 Jul 2026 14:59:05 +0000

Angular apps can stay fast for a long time, until they don't. A lot of performance issues i've debugged had nothing to do with bundle size or server speed. The real problem was change detection doing way more work than it needed.
Here are some common mistakes.

1. Using the default strategy everywhere

Angular's default change detection is convenient, but it checks more often than many apps actually need. For bigger applications, this can become expensive fast. Using OnPush in the right places can reduce unnecessary updates a lot.

2. Calling functions directly in templates

This one is easy to miss. every detection cycle will execute those functions again. If the function is expensive or creates new objects, performance can drop quickly.
Computed values should usually live outside the template.

3. Mutating objects with OnPush

A common mistake. With OnPush, Angular watches references, not deep changes. Mutating and existing object can prevent updates from rendering. Immutable updates make this much more prefictable.

4. Rendering large lists without trackBy

Without trackBy, Angular may recreate DOM elements unnecessarily. On big lists, that gets expensive. A simple trackBy can save a lot of work.

Most Angular performance problems are not caused by Angular. They usually come from small patterns repeated across the app. And change detection is often where those patterns hurt the most.

How to optimize Angular bundle size for faster load times

Alejandro — Fri, 03 Jul 2026 14:45:07 +0000

One of the most common problems I see in Angular projects is bundle size growing way faster than expected.
At first, everything feels fine, then the app grows, dependencies pile up and suddenly your first load is slow, your Lighthouse score drops and users start noticing.
Here are some practical ways to optimize Angular bundle size.

1. Lazy load everything that makes sense

A lot of apps still ship too much code upfront.
Feature modules, admin panels, dashboards or rarely used routes should be lazy loaded so users only download what they need. This alone can make a huge difference.

2. Audit third-party dependencies

Some libraries look small but pull in a lot of extra code. Date libraries, UI kits and utility packages are usually the biggest offenders. Always check if you really need the whole package.

3. Whatch for duplicated imports

It's easy to accidentally import the same heavy dependency in multiple places. This can bloat the final bundle more than expected. Bundle analyzers help a lot here.

4. Use standalone components when possible

Angular's newer architecture can reduce unnecessary module overhead and improve tree-shaking

5. Optimize assets too

Images, fonts and icons are part of your load time. A perfectly optimized Js bundle can still feel slow if assets are heavy

Most Angular performance issues don't come from Angular itself. They come from how the app grows. Bundle size is one of the first places where that shows up.

Why API integrations break when your app scales

Alejandro — Fri, 03 Jul 2026 10:36:58 +0000

API integrations usually feel easy at the beginning. A few requests, some authentications, maybe a webhook or two and everything works fine. Then your app grows; more users, more traffic, more concurrent requests, more dependencies. That's when things start breaking.

1. Rate limits hit faster than expected

What worked for 50 users suddenly fails at 5000.
Without queues, batching or retry strategies, external APIs can quickly become bottlenecks.

2. Small delays become big problems

At scale, even small latency from third-party APIs adds up. One slow dependency can affect the whole user flow. This is why timeouts and fallback strategies matter.

3. Token management gets harder

More users means more sessions, more refreshes and more chances for auth flows to fail. Bad token rotation logic becomes a real problem fast.

4. Error handling becomes architecture

At small scale, you can fix things manually. At bigger scale, every failure needs to be predictable. Logging, monitoring and graceful recovery stop being optional. Scaling an app doesn't just expose performance issues. It exposes weak integrations. An most teams realize it later than they should.

Building reliable API integrations in modern web application

Alejandro — Fri, 03 Jul 2026 10:16:55 +0000

Modern applications depend on APIs more than ever.
Payments, authentication, notifications, analytics, CRMs... most products today rely on multiple third-party services to function properly. Connecting them is usually the easy part.
Making them reliable is where things get difficult.
A lot of API integrations work perfectly during development, but start failing once real users, real traffic and edge cases show up.
Here are some of the most common problemns I keep seeing.

1. Third-party failures are normal

External APIs fail. Timeouts happen. Servers go down. Responses get delayed. If your app assumes every request will succeed, it will eventually break. Retries, fallbacks and proper error handling should be part of the architecture from day one.

2. Authentication gets messy fast

Expired tokens, refresh logic, invalid sessions and revoked credentials create a lot of hidden problems.
A secure auth flows is not just about getting a token. It's about handling the full lifecycle correctly.

3. APIs change over time

Response structures evolve. Fields get renamed, removed or changed.
Without validation and version control, even small changes can break critical features.

4. Rate limits become real at scale

What works with 10 users may fail with 10000. Batching, queues and backoff strategies become necessary much earlier than most teams expect.