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System Design Primer

Master large-scale system design principles and ace your technical interviews with comprehensive guides, real-world solutions, and hands-on examples.

Get StartedInterview Guide

Quick start

Get up to speed with system design fundamentals in minutes

1

Understand the fundamentals

Start with core concepts like performance vs scalability, latency vs throughput, and the CAP theorem. These trade-offs are fundamental to every system design decision.

Performance vs Scalability

Learn when to optimize for speed versus scale

Availability vs Consistency

Understand the CAP theorem and its implications
2

Learn core components

Master the building blocks of distributed systems: load balancers, caches, databases, CDNs, and message queues.
Every large-scale system is built from these fundamental components. Understanding how they work individually and together is crucial.
3

Practice with real problems

Work through actual system design interview questions with detailed solutions, diagrams, and code examples.
Example Problems
• Design Pastebin/Bit.ly - URL shortening service
• Design Twitter - Timeline and search functionality  
• Design a Web Crawler - Distributed web indexing
• Design Mint.com - Personal finance aggregator
4

Use Anki flashcards for retention

Download our spaced repetition flashcard decks to reinforce your learning and retain key concepts for interviews.Get the flashcard decks

Explore by topic

Deep dive into specific areas of system design

DNS

Domain name system and hierarchical resolution

CDN

Content delivery networks and edge caching

Load Balancer

Distribute traffic across multiple servers

Reverse Proxy

Centralize services and add security

Database

RDBMS, NoSQL, replication, and sharding

Cache

In-memory data stores and caching strategies

Asynchronism

Message queues and task queues

Communication

TCP, UDP, RPC, and REST protocols

Security

Encryption, authentication, and authorization

Interview preparation

Real system design interview problems with complete solutions

Design Pastebin

Design a URL shortening service like Bit.ly with hash generation, storage, and redirection at scale.

View solution

Design Twitter

Build a social media timeline and search system with fan-out strategies and real-time updates.

View solution

Design a Web Crawler

Create a distributed web crawler that indexes billions of pages efficiently with politeness policies.

View solution

Scale to Millions on AWS

Learn how to scale a system from one user to millions using AWS services and best practices.

View solution
View all 8 system design problems

Additional resources

Reference materials and real-world examples

Powers of Two Table

Essential memory and storage calculations

Latency Numbers

Performance benchmarks every programmer should know

Real-World Architectures

Case studies from production systems

Company Engineering Blogs

Learn from tech companies’ engineering blogs

Ready to master system design?

Start learning today with our comprehensive guides, real interview problems, and hands-on examples.

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