Web App Architecture | DNS | CDN | Loadbalancer | Gateway | Cloudfront | Redis | TCP/TLS Handshake

In this video, we break down the complete architecture of a modern web application step by step — from the moment a user types a URL into the browser, to how the request is handled by servers, load balancers, caching layers, and databases. If you’ve ever wondered “How does a web app actually work under the hood?”, this video will give you a clear, structured explanation.

We start with the frontend journey:

A user types a URL in the browser.

DNS resolves the domain name into an IP address.

A TLS handshake happens to establish a secure HTTPS connection.

Static assets like images, CSS, JavaScript, and videos are often cached and served from the nearest CDN edge server, reducing latency and improving performance.

If there’s a cache miss, the CDN fetches the asset from the origin server (e.g., an EC2 instance hosting frontend code).

Next, we dive into the backend flow:

The origin server is often fronted by Nginx, which acts as a reverse proxy and load balancer.

API requests from the frontend are routed by Nginx to backend servers (EC2 instances running microservices or a monolithic app).

Backend services handle business logic, interact with databases, and return the response back through Nginx → frontend → browser.

We also cover scalability and performance concepts:

Vertical vs Horizontal Scaling: Adding more power to a single machine vs adding more machines to handle traffic.

Monolithic vs Microservices Architecture: Trade-offs between a single deployable unit vs distributed services with independent scaling.

Caching with Redis: How Redis improves performance by storing frequently accessed data in memory, reducing the load on databases.

CDN advantages: Reduced latency, DDoS protection, global reach, and improved user experience.

By the end of this video, you will understand:

How a simple URL leads to a complete chain of requests and responses.

The role of DNS, CDN, TLS, Nginx, backend servers, and caching layers.

Why companies use load balancers, CDNs, and caching systems to scale efficiently.

The difference between monolithic and microservice architectures and when to use each.

This video is perfect for:

Beginners who want to understand how modern web apps are structured.

Interview preparation for software engineering roles (common system design concepts explained simply).

Developers looking to refresh their knowledge of backend scaling, load balancing, and caching.

If you’re preparing for system design interviews (Google, Amazon, Microsoft, etc.) or simply want to understand how scalable web apps are built, this introduction will set a solid foundation.

💡 Chapters (Suggested):
0:00 Introduction
0:45 User enters URL → DNS & TLS
2:00 CDN and caching of static assets
4:00 Nginx as load balancer and reverse proxy
5:30 Backend servers (monolithic vs microservices)
7:00 Scaling: vertical vs horizontal
8:00 Redis caching explained
9:00 End-to-end request flow recap

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#SystemDesign #WebArchitecture #SoftwareEngineering #BackendDevelopment #Frontend #CDN #Nginx #Redis #Microservices #Monolithic #LoadBalancing #Scaling