Introduction to System Design Interviews
Before any architectural concepts, the course sets you up with the meta-skills of the interview itself. What the interviewer is actually evaluating, how to gather requirements properly, how to do capacity estimation on a whiteboard, and the specific mistakes that tank most candidates before they even start designing.
What is a System Design Interview?
Understand the purpose of system design interviews, focusing on scalability, architecture decisions, trade-offs, and real-world problem-solving skills.
Functional vs. Non-functional Requirements
Master functional vs. non-functional requirements in system design, emphasizing scalability, performance, and trade-offs for building robust, real-world systems.
What are Back-of-the-Envelope Estimations?
Master back-of-the-envelope estimation to assess scalability, performance, and trade-offs using quick calculations in system design interviews.
Things to Avoid During System Design Interview
Learn what to avoid in system design interviews, like skipping trade-offs, ignoring requirements, poor communication, and rigid thinking.
Glossary of System Design Basics
The foundational vocabulary of distributed systems. Each concept is explained with analogies, diagrams, and a "why you care" framing that connects theory back to real interview moments. If you're new to system design, this is where your prep really begins.
System Design Basics
Get familiar with core system design concepts, key architectural components, and building blocks of scalable, distributed software systems.
Key Characteristics of Distributed Systems
Explore key characteristics of distributed systems, including scalability, reliability, availability, efficiency, fault tolerance, and manageability.
Load Balancing
Learn how load balancing improves scalability and availability by distributing traffic using smart algorithms, health checks, and redundancy techniques.
Load Balancing Algorithms
Go deeper into round-robin, least connections, IP hash, weighted algorithms, and how to pick the right strategy for each use case.
Caching
Learn caching strategies to improve system performance, including cache types, eviction policies, read/write methods, and cache invalidation techniques.
Data Partitioning
Learn data partitioning techniques, horizontal, vertical, hybrid, and partitioning criteria to scale databases, improve performance, and balance workloads.
Indexes
Understand how database indexes optimize query performance, enable efficient lookups, and impact write operations in large-scale systems.
Proxies
Learn how forward and reverse proxies improve security, caching, and traffic control by mediating communication between clients and servers.
Redundancy and Replication
Learn how redundancy and replication improve system reliability and availability through failover strategies and synchronous, asynchronous, and semi-synchronous replication.
SQL vs. NoSQL
Compare relational and non-relational databases to understand schema flexibility, scalability, ACID compliance, and ideal use cases for each.
CAP Theorem
Understand why distributed systems must trade off between consistency, availability, and partition tolerance, only two of the three can be guaranteed at any time.
PACELC Theorem
Learn how PACELC extends CAP by showing that even without partitions, distributed systems must balance latency and consistency in replicated environments.
Consistent Hashing
Learn the architecture of scalable systems using consistent hashing for efficient data partitioning, replication, and dynamic node management.
Long-Polling vs WebSockets vs Server-Sent Events
Understand the system design of real-time communication protocols for scalable push-based updates between client and server.
Bloom Filters
Explore space-efficient system design using Bloom filters for fast, probabilistic membership checks with minimal memory and no false negatives.
Quorum
Design highly available distributed systems using quorum-based consistency models to coordinate read/write operations across replicated nodes.
Leader and Follower
Understand the architecture of leader-based replication in distributed systems for consistent writes, fault tolerance, and coordinated data synchronization.
Heartbeat
Learn how distributed systems use heartbeat signals to detect server failures and maintain reliable request routing and availability.
Checksum
Explore how distributed systems ensure data integrity by using checksums to detect and prevent data corruption during transmission.
Quiz
Test your understanding of system design basic concepts before moving into the trade-offs module.
Seen enough already?
Chapters 1 and 2 alone give you more structure than most free resources combined.
System Design Trade-offs
The heart of the course and the thing most other resources skip. Senior-level interviews are won and lost on trade-off conversations. Each lesson takes a common comparison, explains both sides, and shows when each choice is correct. This is the vocabulary that separates "pass" from "strong hire."
Importance of Discussing Trade-offs
Demonstrating trade-offs shows maturity, critical thinking, and real-world design skills crucial for scalable, practical system architecture.
Strong vs Eventual Consistency
Explore consistency models in distributed systems, comparing strong and eventual consistency in terms of latency, availability, accuracy, and scalability trade-offs.
Latency vs Throughput
Understand the difference between latency and throughput, and explore strategies to optimize response time and data processing capacity in systems.
ACID vs BASE Properties in Databases
Understand key differences between ACID and BASE database models, balancing consistency, availability, scalability, and fault tolerance in distributed systems.
Read-Through vs Write-Through Cache
Explore read-through vs write-through caching strategies for improving read performance, data consistency, and integrity in scalable systems.
Batch Processing vs Stream Processing
Compare batch vs stream processing in system design, complexity, resource efficiency, continuous vs scheduled data flow, and real-time responsiveness.
Load Balancer vs. API Gateway
Understand differences between Load Balancer and API Gateway in scalable architectures, traffic distribution, request routing, API management, and availability.
API Gateway vs Direct Service Exposure
Explore API Gateway vs Direct Service Exposure in distributed systems, compare centralized routing and security with direct access and reduced latency.
Proxy vs. Reverse Proxy
Understand how proxies and reverse proxies manage client and server traffic in distributed system design to improve security, caching, and scalability.
API Gateway vs. Reverse Proxy
Learn the difference between API Gateways and Reverse Proxies in distributed systems, focusing on routing, security, load balancing, and orchestration.
SQL vs. NoSQL
Compare SQL vs NoSQL databases based on schema structure, scalability, ACID compliance, flexibility, and best use cases in system design.
Primary-Replica vs Peer-to-Peer Replication
Understand Primary-Replica vs Peer-to-Peer replication models, including data flow, consistency, scalability, fault tolerance, and use cases.
Data Compression vs Data Deduplication
Learn the differences between data compression and deduplication for optimizing storage, focus, scope, efficiency, and best-use scenarios.
Server-Side Caching vs Client-Side Caching
Understand server-side vs client-side caching, how they differ in location, control, performance impact, and best use across web apps.
REST vs RPC
Learn the architectural differences between REST and RPC, including stateless resource handling vs. procedure calls, flexibility, scalability, and performance trade-offs.
Polling vs. Long-Polling vs. WebSockets vs. Webhooks
Compare real-time delivery strategies, Polling, Long-Polling, WebSockets, and Webhooks, for scalable, event-driven system communication.
CDN Usage vs Direct Server Serving
Learn when to use a Content Delivery Network vs direct server hosting based on traffic scale, geographic distribution, and caching efficiency.
Serverless Architecture vs Traditional Server-based
Learn serverless system design benefits like dynamic scaling and reduced ops versus traditional server hosting with full control and overhead.
Stateful vs Stateless Architecture
Explore the architecture of stateful vs stateless systems, comparing session handling, scalability, and design trade-offs for APIs and web services.
Hybrid Cloud Storage vs All-Cloud Storage
Explore hybrid cloud vs all-cloud storage architectures, balancing scalability, compliance, and control for secure, flexible enterprise data strategies.
Token Bucket vs Leaky Bucket
Learn how Token Bucket and Leaky Bucket algorithms manage network traffic shaping, rate limiting, and handling of bursty data.
Read Heavy vs Write Heavy System
Explore how system design varies for read-heavy and write-heavy workloads with techniques like batching, replication, and data partitioning.
System Design Problems
The payoff chapter. Real interview questions from top tech companies, each walked through end-to-end with the course's step-by-step framework: requirements, estimation, high-level design, detailed components, bottlenecks, and scaling. Every architecture comes with interactive diagrams.
System Design Interviews: A Step-by-Step Guide
The master framework for approaching any system design question. Requirements gathering, estimation, high-level design, and drill-down into components.
System Design Master Template
A reusable template you can apply to any design question, covering every step from initial clarification through final scaling discussion.
Designing a URL Shortening Service like TinyURL
The classic warm-up problem. Hashing strategies, collision resolution, read-heavy caching, and database choices at billion-request scale.
Designing Pastebin
Similar to URL shortener but with content storage. Learn how to extend one design into a related but more complex problem.
Designing Instagram
Photo upload and storage, feed ranking, scaling to billions of users, and handling celebrity accounts with fanout strategies.
Designing Dropbox
File sync, chunking, conflict resolution, and secure distributed storage. A deep dive into one of the most common senior-level questions.
Designing Facebook Messenger
Real-time message delivery, presence, read receipts, and group chats. Persistent connections, message ordering, and offline users at scale.
Designing Twitter
Timeline generation, fanout-on-write vs fanout-on-read, and the hybrid approach Twitter actually uses for high-follower accounts.
Designing YouTube or Netflix
Video encoding pipelines, CDN distribution, recommendation systems, and bandwidth-efficient streaming at planetary scale.
Designing Typeahead Suggestion
Trie structures, popularity ranking, personalization, and serving suggestions with sub-50ms latency at search-engine scale.
Designing an API Rate Limiter
Token bucket, sliding window, and distributed rate limiting. A short but deceptively tricky design question that shows up across FAANG.
Designing Twitter Search
Inverted indexes, real-time indexing, ranking tweets, and serving billions of search queries per day.
Designing a Web Crawler
Politeness policies, URL frontiers, duplicate detection, and distributed crawling at the scale of the public internet.
Designing Facebook's Newsfeed
Feed ranking, pre-computation vs on-the-fly generation, and the ML-driven ranking signals used at social media scale.
Designing Yelp or Nearby Friends
Geospatial indexing with quad-trees and geohashing. The foundational techniques behind every location-based service.
Designing Uber Backend
Real-time driver and rider matching, geospatial indexing at scale, surge pricing, and payment processing. One of the most commonly asked problems.
Designing Ticketmaster
Concurrency, inventory locking, high-volume traffic spikes for popular events, and preventing double-bookings.
Additional Resources
Supplementary reading, reference diagrams, and external resources to extend your practice beyond the core curriculum.
Appendix
Reference material you'll come back to. Use these as a study aid during prep and as a last-mile review checklist in the days before your interview.
System Design Interview Checklist
A printable checklist covering every stage of the interview: clarifying questions, estimation, design, drill-down, and wrap-up.
Further Reading and Resources
A curated list of papers, blog posts, and books that complement the course for engineers who want to go deeper into specific topics.