Backend With Sushil

25/07/2026

🚀 5,000 Followers on Facebook! ❤️

What started as an effort to simplify backend engineering concepts has now become an amazing community of 5,000 people.

Thank you to everyone who watches, comments, shares, and supports my content. It truly means a lot!

If you enjoy learning about:
✅ System Design
✅ Kafka
✅ Backend Architecture
✅ Production Engineering
✅ Interview Preparation
✅ Real-world Software Engineering

Let’s stay connected everywhere!

📸 Instagram: https://www.instagram.com/backendwithsushil/

▶️ YouTube: https://www.youtube.com/

I’ll keep sharing practical, interview-focused, and production-ready backend content to help you grow as an engineer.

💬 What backend topic should I cover next? Drop your suggestions in the comments!

Backend aur System Design simple Hindi mein

25/07/2026

🎬 System Design Series | Episode 49

😱 Can Kafka lose messages?

One of the most asked Kafka interview questions.

The answer is YES... but only if Kafka isn't configured correctly.

In this episode, you'll learn:
✅ Why Kafka can lose messages
✅ What acks=0, acks=1, and acks=all mean
✅ Which setting is used in production
✅ Interview-ready explanation in under 60 seconds

📌 Save this reel for your next backend interview.

💬 Question: Which acks value do you use in production and why?

Follow for daily Backend Engineering, System Design, Kafka, and Interview content.

Keywords: Kafka, Apache Kafka, Kafka interview questions, Kafka message loss, Kafka acks, acks=0, acks=1, acks=all, Kafka producer, backend engineering, system design, distributed systems, microservices, software engineering, scalable systems, tech interview, backend developer, Java, Node.js, production systems, interview preparation.

25/07/2026

🚀 Confused about Threads and why they're so important in backend development and interviews?

In this video, I explain Threads in simple Hinglish with real-world examples.

✅ What is a Thread?
✅ Process vs Thread
✅ Why Threads are Lightweight
✅ Shared Memory Explained
✅ Context Switching
✅ Multithreading in Real Applications
✅ Backend & System Design Interview Questions

Whether you're preparing for backend interviews, learning Operating Systems, or improving your backend engineering knowledge, this video will help you build a strong foundation.

💬 Question: Have you ever worked with multithreading in your projects? Share your experience in the comments!

👍 Follow BackendWithSushil for daily backend engineering, system design, and interview preparation content.



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20/07/2026

😨 Why is Kafka so fast?

Most developers answer:
"Because Kafka is distributed."

That's true... but it's not the complete answer.

The real reason is Partitions.

Kafka splits a Topic into multiple Partitions, allowing Producers and Consumers to work in parallel, which helps Kafka achieve high throughput and handle millions of messages efficiently.

💾 Save this reel for your next backend interview.
📤 Share it with a friend preparing for system design interviews.



Keywords: Kafka, Kafka Partitions, Apache Kafka, System Design, Backend Development, High Throughput, Parallel Processing, Distributed Systems, Kafka Interview Questions, Software Engineering, Microservices, Producer Consumer, Event Driven Architecture, Backend Interview, Scalable Systems, Tech Reels, BackendWithSushil

19/07/2026

🚀 EP43 | Kafka Mini Series

Kafka ke paas agar 1 crore messages aa jaye... to usse kaise pata chalta hai ki kaunsa message kahan rakhna hai? 🤯

Answer hai Kafka Topics.

Har type ke message ka apna Topic hota hai:
🛒 order-created
💳 payment-successful
👤 user-registered

Isse messages organized rehte hain aur services sirf wahi events read karti hain jo unhe chahiye.

Lekin... 🤔

Agar ek hi Topic mein 100 crore messages aa jaye... to Kafka slow nahi ho jayega?

⚡ Next Episode: Kafka Partitions

💬 Question: Agar aapko Orders aur Payments ke liye Kafka use karna ho, to kitne Topics banaoge?

Keywords: Kafka, Apache Kafka, Kafka Topics, System Design, Event Driven Architecture, Microservices, Distributed Systems, Backend Development, Software Engineering, Java, Spring Boot, Node.js, NestJS, Scalable Systems, Kafka Tutorial, Tech Reels

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18/07/2026

🚀 System Design Series | Episode 42

Why do companies like Netflix, Uber, Amazon, and LinkedIn use Apache Kafka?

Imagine your Email Service goes down. Should your Order Service fail too?

In this video, I explain why modern microservices use Kafka to build decoupled, scalable, and reliable systems using a simple real-world e-commerce example.

📌 In this video you'll learn:

What problem Kafka solves
Why direct service-to-service communication is risky
Event-driven architecture
How Kafka decouples microservices
Why Kafka improves scalability and reliability

🎯 Next Episode: Producer vs Consumer

If you're preparing for Backend Interviews, System Design, or learning Microservices, this Kafka series is for you.

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17/07/2026

😨 Ever wondered how hackers guess your password?

Most people think hackers somehow decrypt passwords.

But that's usually not how it works.

If a database gets leaked, hackers can keep trying thousands—or even millions—of password guesses, generate the hash for each one, and compare it with the leaked hash.

The moment a hash matches, they find the original password.

This technique is called a Brute Force Attack.

That's exactly why strong passwords, Salt, Pepper, and algorithms like bcrypt or Argon2 are so important. They don't make hacking impossible—but they make every password guess so slow and expensive that cracking passwords becomes practically impossible.

🔐 Use strong passwords. Your first layer of security starts with you.

💬 Question: Have you ever guessed a friend's password during your school or college days? 😅

Follow for more Backend Engineering & System Design content.

Keywords: Brute Force Attack, Password Security, Password Hashing, Hash, Salt, Pepper, bcrypt, Argon2, Cyber Security, Backend Development, System Design, Authentication, JWT, Database Security, Software Engineering.

16/07/2026

🚨 Aaj bhi bahut saare developers ko lagta hai JWT encrypted hota hai...

Lekin sach ye hai... JWT encrypted hota hi nahi. 😳

JWT sirf Base64 encoded hota hai, isliye koi bhi uska Header aur Payload dekh sakta hai.

Lekin iska matlab ye nahi ki koi JWT modify karke login kar sakta hai.

✅ Server har request par JWT Signature verify karta hai.

Agar token ka ek bhi character change hua...

❌ Token instantly reject ho jata hai.

👉 Kabhi bhi JWT ke andar Password, OTP ya koi bhi sensitive information mat store karna.

💬 Question: Agar JWT encrypted nahi hota, to phir secure kaise rehta hai? Comment mein batao! 👇

Keywords: JWT, JSON Web Token, Authentication, Authorization, JWT Security, Backend Development, System Design, API Security, Web Security, Node.js, Express.js, OAuth, Access Token, Refresh Token, JWT Signature, Base64 Encoding, Backend Engineer, Software Engineer, Programming, Coding, Tech Reels

16/07/2026

You’ve clicked "Continue with Google" hundreds of times.

But have you ever wondered what actually happens behind the scenes? 🤔

Many developers think Google simply sends a JWT. The reality is different.

In this episode, you'll learn:
✅ What OAuth actually does
✅ Where JWT fits in
✅ Why JWT and OAuth are not competitors
✅ How Google Login really works

This is one of the most common authentication concepts asked in backend interviews.

Episode 36 of my System Design Series.

Follow for more backend engineering and system design content.

Keywords

Google Login, Continue with Google, OAuth, JWT, Authentication, Authorization, OAuth 2.0, JWT Token, Backend Development, Backend Engineer, System Design, API Security, Login Flow, Authentication Flow, Google OAuth, Access Token, Refresh Token, Software Engineer, Tech Interview, Interview Preparation

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15/07/2026

😨 Hacker ne database chura liya... Password decrypt bhi nahi hua. Phir bhi usse pata chal gaya ki do users same password use kar rahe hain. 🤯 Kaise? Aaj ke episode mein samjho Salted Hashing aur kyun modern production applications sirf hashing par depend nahi karti. Agar backend interviews ki preparation kar rahe ho ya real-world system design seekhna chahte ho, ye concept zaroor aana chahiye. 💬 Question: Agar do users ka hash same ho, iska kya matlab ho sakta hai? Answer comments mein batao.

Keywords: Backend Development, System Design, Password Security, Salt, Salted Hashing, bcrypt, Argon2, Authentication, Backend Interview, Node.js, Cyber Security, Database Security, Production Systems, Software Engineer, Interview Preparation