Series

System Design Interview

Notes from system design chapters and practice designs, covering scaling, estimation, rate limiting, storage, feeds, chat, video, file sync, and trading systems.

March 2026 · 16 chapters

System Design Chapter 1: Scale From Zero To Millions Of Users

Notes from System Design Interview Chapter 1 on scaling from a single server to distributed systems, load balancing, caching, and databases.

system-design
scalability
architecture

System Design Chapter 2: Back-of-the-envelope Estimation

Notes from System Design Interview Chapter 2 on estimation, capacity planning, QPS, storage, bandwidth, and system scale.

system-design
estimation
capacity-planning

System Design Chapter 3: A Framework For System Design Interview

Notes from System Design Interview Chapter 3 on approaching system design interviews with requirements, estimates, APIs, data models, and tradeoffs.

system-design
interviews
architecture

System Design Chapter 4: Design A Rate Limiter

Notes from System Design Interview Chapter 4 on rate limiter requirements, algorithms, distributed counters, and tradeoffs.

system-design
rate-limiting
distributed-systems

System Design Chapter 5: Design Consistent Hashing

Notes from System Design Interview Chapter 5 on consistent hashing, data distribution, virtual nodes, and rebalancing.

system-design
consistent-hashing
distributed-systems

System Design Chapter 6: Design A Key-Value Store

Notes from System Design Interview Chapter 6 on key-value store design, APIs, partitioning, replication, consistency, and failure handling.

system-design
databases
key-value-store

System Design Chapter 7: Design A Unique ID Generator In Distributed Systems

Notes from System Design Interview Chapter 7 on distributed unique ID generation, UUIDs, tickets, Snowflake IDs, and tradeoffs.

system-design
distributed-systems
id-generation

System Design Chapter 8: Design A URL Shortener

Notes from System Design Interview Chapter 8 on URL shortener requirements, APIs, hashing, redirects, and storage design.

system-design
url-shortener
architecture

System Design Chapter 9: Design A Web Crawler

Notes from System Design Interview Chapter 9 on crawler architecture, URL frontier design, politeness, deduplication, and storage.

system-design
web-crawler
architecture

System Design Chapter 10: Design A Notification System

Notes from System Design Interview Chapter 10 on notification architecture, push systems, queues, providers, and reliability.

system-design
notifications
architecture

System Design Chapter 11: Design A News Feed System

Notes from System Design Interview Chapter 11 on news feed generation, fanout, ranking, caching, and scaling.

system-design
news-feed
architecture

System Design Chapter 12: Design A Chat System

Notes from System Design Interview Chapter 12 on chat architecture, realtime delivery, presence, storage, and synchronization.

system-design
chat
realtime

System Design Chapter 13: Design A Search Autocomplete System

Notes from System Design Interview Chapter 13 on autocomplete requirements, trie-based designs, ranking, updates, and scaling.

system-design
autocomplete
search

System Design Chapter 14: Design YouTube

Notes from System Design Interview Chapter 14 on video upload, transcoding, storage, CDN delivery, metadata, and scaling.

system-design
video
cdn

System Design Chapter 15: Design Google Drive

Notes from System Design Interview Chapter 15 on file storage, metadata, upload/download APIs, sync, and conflict handling.

system-design
file-storage
synchronization

System Design: Design Stock Trading Platform

Notes on designing a stock trading platform, covering trading flows, market data, consistency, latency, and order execution.

system-design
trading
architecture