Skip to main content

System Design Most Important Interview Question for Job / Placement

What is System Design?

System design is the process of defining the architecture, components, modules, interfaces, and data flow of a system to satisfy specific requirements. It provides a blueprint for building complex software or hardware systems, ensuring they are scalable, reliable, efficient, and easy to maintain.

Whether you’re creating a small application or a large-scale distributed system, system design helps you break down big problems into manageable pieces, choose the right technologies, and plan for growth.

Key Elements of System Design:

  • High-Level Design (HLD): Outlines the overall system architecture, including technologies, services, APIs, and data models.

  • Low-Level Design (LLD): Focuses on the implementation details such as class diagrams, logic flow, and database schema.

  • Scalability & Performance: Ensures the system can handle increasing traffic and data without degrading performance.

  • Reliability & Fault Tolerance: Designs for uptime and graceful failure handling.

  • Security & Maintainability: Incorporates best practices to keep the system safe and adaptable over time.


System Design is a crucial topic in tech interviews, especially for mid to senior-level roles. It tests your ability to design scalable, efficient, and reliable systems—just like those used at top tech companies!

This article covers some of the most commonly asked System Design interview questions to help you prepare and ace your next interview.

Important Question (Basic to Advanced):

  • What is System Design?
  • Functional vs Non Functional Requirements
  • What are the components of System Design?
  • System Design Life Cycle | SDLC (Design)
  • Structured Analysis and Structured Design
  • System Design Strategy
  • Database Sharding - Concept
  • Horizontal and Vertical Scaling
  • Load Balancer in System Design
  • Routing requests through Load Balancer
  • Latency and Throughput in System Design
  • Object-Oriented Analysis and Design
  • Difference between Structured and Object-Oriented Analysis
  • What is Low Level Design or LLD
  • Data Structures and Algorithms for System Design
  • Event-Driven Architecture
  • Difference between Authentication and Authorization
  • What is API Gateway
  • What is Data Encryption?
  • Design Patterns
  • Code Optimization Techniques
  • Unit Testing
  • Integration Testing
  • CI/CD: Continuous Integration and Continuous Delivery
  • Introduction to Modularity and Interfaces In System Design
  • Data Partitioning Techniques
  • Class Diagrams | UML
  • What is High Level Design
  • Availability in System Design
  • Consistency in System Design
  • Reliability in System Design
  • CAP Theorem
  • Difference between Process and Thread
  • Difference between Concurrency and Parallelism
  • Load Balancer
  • Consistent Hashing
  • Content Delivery Network (CDN) in System Design
  • Caching in System Design
  • Cache Eviction Policies
  • Message Queues
  • Communication Protocols
  • Network Protocols and Proxies in System Design
  • Unified Modeling Language (UML)

Most Important Topics :

  • Design URL Shortening Service
  • Design Dropbox
  • Design Twitter
  • System Design Netflix - A Complete Architecture
  • System Design of Uber App - Uber System Architecture
  • Design Book My Show
  • Designing Facebook Messenger
  • Designing WhatsApp Messenger
  • Designing Instagram

Where to Start? 🤔
With so many online sites and resources it’s very natural that one will be confused. So, to make things easier I will provide you some resources here.

Resources 😛