JavSyS 🧑🏻‍💻 Javier L. Avellán

Fullstack developer - Desarrollador de software 🧑🏻‍💻

[FILMZ @moviesfilmz]

🎬 Dime una película que te haya dado MUCHÍSIMO MIEDO sin enseñar prácticamente NADA.

Pero no me digas The Blair Witch Project, Los Otros ni The Witch.

Quiero conocer muchas de este estilo.

Os leo 👇

[KrunalSinh Sisodia @krunalbuilds]

Interviewed a Senior Backend Engineer today.

Knew REST APIs, polling, WebSockets, SSE — all of it.

Then I asked:

"You're building a real-time dashboard.

Stock prices update every 500ms.

You have 100,000 concurrent users watching.

Option A: each client polls the API every 500ms.
Option B: WebSocket connection to each client.
Option C: Server-Sent Events.

At 100,000 users — each option has a critical problem that will break your infrastructure.

What are they — and which one do you choose?"

Silence.

Your turn:

100k concurrent users ❌
500ms updates required ❌
Polling vs WebSockets vs SSE ❓

What breaks at scale — and which do you actually pick? 👇

(Most devs pick WebSockets. Most are wrong for this use case.)

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

Bus 81 - 1 de la Delia siguen cobrando 0.70 ctvos el pasaje
@ATD_Duran

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@enriquezvma @Polificcion @RobertoGranda17 Pelé sólo brilló en el 70, los demás mundiales casi ni jugó y era en una época donde el fútbol era lento y los atletas no eran tan desarrollados en la parte física

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@luis_Wr04 @TndenciaStream No hagas quedar mal a Ecuador cojudo, apoya a Sudamérica, apoya a Argentina

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@lahoraecuador Lo voy a seguir a Gastón para armar las apuestas

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@IngridHerreraP @radiocentroec @janethinostroza Correcto, pero lo que se reclama es que los anteriores corruptos ahora vengan a dar clases de ética y moral. Deberían quedarse callados si tuvieran un ápice de vergüenza

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@Suryanshti777 COURSE

[Suryansh Tiwari @Suryanshti777]

Most developers never crack high-paying jobs...

Not because they can’t code —
but because they FAIL system design.

That’s the real filter.

So I’m giving away 2 powerful resources:

• System Design for Beginners
• System Design Interview Prep

Learn how real scalable systems are built.
The same concepts used at top tech companies.

This is the skill that separates ₹5L devs from ₹50L+ engineers.

Free for a limited time.

How to get it:

1. Follow me (so I can DM you)
2. Like + RT
3. Comment “COURSE”

Ill DM

Bookmark this if you’re serious about leveling up.

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@pantasec RUTA GRATIS

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@pushpendratips Web

[Leonard Rodman @RodmanAi]

System Design becomes EASY when you follow these:

1. Fundamentals
https://t.co/3El7u5v1at

2. API Design
https://t.co/y13ymiLR9c

3. Load Balancing
https://t.co/QP3ZH6iZxH

4. Message Queues
https://t.co/69i7a9FlDC

5. Rate Limiting
https://t.co/NcuCcfhY01

6. Caching
https://t.co/ZEmAMj5nb5

7. Sharding & Partitioning
https://t.co/KZcn6xrdPr

8. Database Replication
https://t.co/diWvyI4QZW

9. Consistent Hashing
https://t.co/JYZG24AXIf

10. CAP Theorem
https://t.co/8MQRmb3qy8

11. Microservices
https://t.co/pH29HRu3WJ

12. Fault Tolerance
https://t.co/hMAqL9i1Nv

13. Scalability
https://t.co/3sP0CkZTGF

14. Event-Driven Architecture
https://t.co/BAYffQm2td

15. Service Discovery
https://t.co/8BaRzHIaFk

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@arceyul Faltó yo por favor

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@jarapolitica @Expresoec responda

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@livingdevops Terraform

[Akhilesh Mishra @livingdevops]

Terraform is the one skill that separates DevOps engineers who click through consoles from those who deploy infrastructure in seconds.

I've had written a comprehensive "Terraform Handbook for DevOps Engineers" ebook that thousands of people loved

and I'm giving it away for free.

To get it for free, just do 3 things.
✓ Follow me (for DM access)
✓ Retweet this post
✓ Comment "Terraform"

And I will personally send you that.

P.S. If i missed sending you due to some issues, just DM me and I will share

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@selinatasnim1 Gemini

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@atikcoder0 HK

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@arceyul Hasta ahora sigo esperando los prompts

[JavSyS 🧑🏻‍💻 Javier L. Avellán @tenshijavier]

@arceyul IA