Kushal Vijay

Which topic you would like to see in future videos?

1 day ago | [YT] | 10

Kushal Vijay

Back in 2014, WhatsApp handled 50 billion messages daily with just 32 engineers...💯

Instagram needed 150+ engineers. Twitter had 1,500+ before Elon took over. WhatsApp in 2014? Only 32 people ran the entire backend serving 450 million MAU.

Most companies use Java or Python for their backend. WhatsApp chose Erlang, a language built for telecom systems in the 1980s.

Erlang treats every user connection as a lightweight process. One server can handle millions of these processes simultaneously without choking.✍🏻

When one process crashes, it doesn't take down the system. Others keep running. It's designed for things to fail without causing chaos.

When Facebook acquired WhatsApp for $19 billion in February 2014, they were processing 50 billion messages daily with only 32 engineers and 450 million monthly active users.💵

Not because they had fancy features. Because their architecture was so simple and efficient that it barely needed maintenance.👷🏻

No recommendation algorithms. No complex feeds. No advertising infrastructure. Just messaging done really, really well.

In Interviews, When asked "Design WhatsApp," most of us would jump to:
- Use WebSockets for real-time communication
- Store messages in Cassandra
- Add Redis for caching

WhatsApp chose Erlang because lightweight processes make handling millions of concurrent connections simple. System design not about talking which company uses which tech,it is about explaining why the choices make sense.

Reading about WhatsApp's architecture won't prepare you for the follow-ups :
"How do you handle message ordering in group chats?"
"What happens when a user is offline?"
You need to practice explaining these decisions out loud when someone challenges your logic.

Tools like Final Round AI help with this. You articulate your architecture, handle pushback, learn to defend choices or realize your reasoning has gaps. It also provides detailed feedback in specific areas and it’s free to use.❤️

Note: Today WhatsApp has significantly more engineers. This post covers their 2014 architecture at the time of Facebook acquisition.

#techcareers #engineering #whatsapp #interviews

1 week ago | [YT] | 99

Kushal Vijay

2025 was not my year 💔
.
.
.
A person who used to be afraid of flying, boarded over 40+ flights this year. ✈️


A person who was very shy in school , Crossed 100K Subscribers on YouTube and 300K followers on Instagram.🌐

A person who had stage fear in college, Visited over 20 Colleges for Talks and Events.🎓

A person who used to hate travelling, visited 20+ cities this year. 🚏

A person who started with the Electronics branch, Did impactful contributions through work at Microsoft. 👨🏻‍💻

Honoured to awarded AI Innovator of the Year at LinkedIn Summit in Bareilly.📜

Invited as a speaker at PyCon Japan, Talked about AI Agents in Production Infrastructure. 🎤

Did my 2nd solo International trip to my bucket list destination Japan .🎴

Met so many amazing content creators, entrepreneurs, CEOs, COOs, CMOs, Founders, Engineers, Managers, and people from various walks of life.💯

Mentored thousands of students through different Channels. ❤️

Made decent money with my Job, Sponsorships & Investments. 💵

Also, Started learning japanese.🏊

Last but not least, FAILED a lot.📎

- Wanted to travel abroad with my family but couldn’t make it.
- Wasn’t able to reach the investment goals.
- Wasted a lot of time watching useless content, overthinking and affecting mental health.
- Failed a lot of career and opportunities

The calendar changed pretty quickly this year but like always it was a good one.

HAPPY NEW YEAR EVERYONE ❤️
Wishing you peace and success in 2026

Onto bigger things...
#happynewyear #newyearwrap

Skip the Carousel

1 2 3 4 5 6 7 8 9 10

1 week ago | [YT] | 134

Kushal Vijay

YouTube buffers at 240p. Netflix streams 4K without a pause...💯

Same internet. Same device. How is that even possible?

The difference isn't your WiFi. It's the BUSINESS MODEL.

🎬 YouTube's Strategy (Reactive):

You click play, It checks your current speed. Picks a quality level. If speed drops, quality drops and buffering happens. It's reacting to problems as they occur.

📺 Netflix's Strategy (Predictive):

Before you even click play, AI predicts your network pattern. Pre-loads multiple quality versions and switches seamlessly between them. Anticipates congestion during peak hours. It's preventing problems before they happen.

Research shows Netflix's AI can save up to 50% bandwidth while keeping quality high.

YouTube wants you to buffer sometimes. Why?

💸 The Cost Reality, YouTube serves 1 BILLION hours daily. Mostly free, ad-supported.

If every video streamed at max quality, their infrastructure costs would explode.

So they optimize for "good enough" quality to serve more people.

Netflix charges $15-20/month. You're paying for that smooth experience. They optimize for perfect streaming, not reaching maximum people. Every "buffering problem" is actually a business decision.

Other examples:

Spotify never buffers - Pre-loads next 3 songs 
Instagram Stories never lag - Pre-cached on app open
Twitter videos buffer constantly - Reactive loading to save costs
The "flaw" you see is the feature someone else chose.

Which streaming platform frustrates you the most?

#techcareer #jobs #systemdesign

2 weeks ago | [YT] | 99

Kushal Vijay

You delete a tweet. It disappears from YOUR screen instantly. But it stays live for 30-60 seconds on everyone else's feed...💯

This isn't a bug. It's preventing something way worse.🚨

You tweet something controversial. It goes viral. 10,000 retweets in 5 minutes and out of panic you delete that.

If Twitter/X deleted it instantly from EVERYONE'S screen at once? 👀

They'd need to send 10,000+ deletion commands to 10,000+ different servers simultaneously.🌐

Distributed systems can't guarantee instant consistency across millions of devices.💻

Let’s learn about CAP theorem today, you can't have Consistency + Availability + Partition tolerance all at once.

Twitter showsyou instant deletion (good UX), but propagates slowly.

That 30-60 second delay, how it’s helpful. In 2014, people discovered they could:
1. Post illegal content
2. Screenshot it with timestamp
3. Delete it instantly
4. Claim "I never posted that, must be Photoshop"

The delay creates a proof window where others can screenshot the real tweet with a timestamp. Twitter turned a technical limitation into a security feature.

The same system that seems broken (slow deletion) prevents false accusations and evidence tampering. 🗣️

Distributed systems trade-off. But the delay also creates evidence windows preventing false denial attacks.

Other examples:
- WhatsApp: "Deleting for everyone" only works within 1 hour (prevents abuse)
- Gmail: "Undo send" gives 30-second window (prevents regret, creates proof)
- GitHub: Deleted repos stay in cache for 90 days (prevents supply chain attacks)

Every "flaw" in system design might be a feature you don't understand yet.
If you like this one, I’ll be covering a lot more interesting usecases in the upcoming posts.📈

Can you tell why YouTube buffers at 240p but Netflix never buffers at 4K?

hashtag#techcareers hashtag#engineering hashtag#story hashtag#career

1 month ago | [YT] | 136

Kushal Vijay

IIT placements started December 1st and Sharma ji ka beta already got 2.8 crore offer
Now every parent is questioning their child's future...💯

The WhatsApp forwards have begun. "Beta dekho, IIT BHU mein 17 students ko 1 crore+ mila!" 🗣️

What they DON'T forward: 1,701 students registered. Only 17 crossed ₹1 crore. That's 1%. 📉

Highest package: ₹2.8 crore (Da Vinci Trading)
IIT BHU: Highest ₹1.67 crore, minimum ₹47.19 lakh
IIT Roorkee: 8 international offers, 428 domestic offers in FIRST SLOT alone

Now Here's What Your Family Group Won't Tell You:🔇

- 20+ companies BANNED from placements this year bcz They cancelled job offers last year. Some as late as June/July - right before joining dates.

- Students with confirmed offers couldn't appear for other interviews. Then offers got revoked. Career destroyed. Mental breakdown. A year wasted.

- IIT students are REJECTING ₹20-25 lakh PPOs because they think they're "too low." Why? Because aunties are comparing them to the 0.1% who got ₹2.8 crore.

- Da Vinci Trading, NK Securities, Optiver, IMC Trading, APT Portfolio. Not Google. Not Microsoft. Trading firms that hire 2-4 students per IIT.

- They want elite math olympiad kids who can code algorithms that move billions in milliseconds. That's NOT most students. And that's perfectly fine.

- IIT Delhi: 1,200+ offers for 1,150 students. Almost everyone is getting placed. Great packages by any standard. But it FEELS like failure when your relatives compare you to 1 student out of 1000.

Stop measuring your average against someone else's outlier.❤️

To every parent: Your child getting placed from IIT is incredible. Stop comparing them or raising expectations to the 0.1%. You're destroying their mental health.

Are you celebrating your placement or feeling inadequate because of someone else's crore package?

#iit #placements #career #story

1 month ago | [YT] | 151

Kushal Vijay

Your salary just changed and nobody told you...1

Government implemented new labour codes on November 21st and your next payslip will look very different.

The govt just consolidated 29 labour laws into 4 codes. Sounds boring until you realize this affects EVERY salaried employee in India.

1. Your Take-Home Salary Is About To Drop

New rule: Basic salary must be minimum 50% of CTC. Most companies kept basic at 30-35% to reduce PF deductions and give you more in-hand salary. Your CTC stays the same. Your bank account sees less money.

2. Fixed-Term Employees Gratuity After 1 Year Permanent employees still need 5 years but Fixed-term/ contract now eligible after just 1 year. Companies that hire on contract basis will see costs jump 20-30%. Slower hiring for freshers initially as companies

adjust budgets.

3. Gig Workers Finally Get Social Security Platform workers (Swiggy, Uber, Zomato) now covered under social security. Aggregators must contribute 1-2% of annual turnover for worker benefits. This is huge for 24 million gig workers in India.

Companies are quietly restructuring salary components right now This will slow down fresher hiring because employees cost will imcrease 20%

#labourlaws #news #india

1 month ago | [YT] | 77

Kushal Vijay

If Microsoft, Google, Amazon doesn't come to your College for Hiring.
They are hiring Off-Campus right now
yt.openinapp.co/8nleg

1 month ago | [YT] | 74

Kushal Vijay

Spoke at UP's first LinkedIn Summit yesterday. 700+ students. 💯

Thanks to Tisha and Aviral for the opportunity. Kudos to the fellow speakers Darika, Riya, Vrinda, Vishnu, Shawrya for sharing their experiences.❤️


Grateful to Mr. Parth Parth and the entire team for honoring me with the “AI Innovator of the Year” award.🚀

Also met the viral sensation and a great comic, Ashish Solanki.

Skip the Carousel

1 2 3 4 5

1 month ago | [YT] | 98

Kushal Vijay

HAPPY Diwali to you All 🪔❤️

I wish this diwali brings you a lot of joy and growth. Rooting for your success ✨️

2 months ago | [YT] | 61