System Design interview preparation course
12 pattern families, 73 lessons, about 31 hours of reading, and 8 families marked Interview Soon for the rounds that are close.
A system design interview asks you to take a one-line product brief — a URL shortener, a chat app, a news feed — and turn it into an architecture you can defend for forty-five minutes: the API, the data model, the storage engine, the caches, the queues, and the failure modes that follow from each choice.
This course splits that skill into pattern families. Each family is a group of decisions that keep coming back across products, and each lesson inside it is one decision with its trade-offs written out: what it buys you, what it costs, and the sentence an interviewer expects when they ask why.
Every family below is a page of its own with the lessons it contains, so you can read the curriculum end to end or jump to the one topic your next interview turns on.
The 12 system design pattern families
The 45-minute interview framework, estimation with modern numbers, and CAP theorem.
6 lessons · about 2 hours · Interview Soon · 1 worked case study
Protocols (REST, gRPC, WebSocket, SSE), API design, pagination, and idempotency.
5 lessons · about 2 hours · Interview Soon · 1 worked case study
SQL vs NoSQL decision tree, replication, sharding, and indexing strategies.
7 lessons · about 3 hours · Interview Soon · 2 worked case studies
Cache-aside, write-through, failure modes, and when NOT to cache.
5 lessons · about 1.5 hours · Interview Soon · 2 worked case studies
Kafka vs SQS, delivery guarantees, idempotent consumers, and event-driven patterns.
10 lessons · about 1.5 hours · Interview Soon · 5 worked case studies
- Queue Fundamentals — Core lesson.
- Delivery Guarantees & Idempotency — Core lesson.
- Event-Driven Patterns Deep Dive — Depth lesson.
- Kafka Deep Dive — Depth lesson.
- Stream Processing — Depth lesson.
- Design YouTube — Core lesson, worked case study, about 60 minutes, asked at Google, Netflix.
- Design a Webhook Delivery System — Depth lesson, worked case study, about 45 minutes, asked at Stripe.
- Design a Notification System — Depth lesson, worked case study, about 60 minutes, asked at Meta, Amazon.
- Design a Web Crawler — Depth lesson, worked case study, about 60 minutes, asked at Google, Amazon, Microsoft.
- Design a Job Scheduler — Depth lesson, worked case study, about 60 minutes, asked at Airbnb, Uber, Stripe.
Consistent hashing, read vs write scaling, fan-out strategies, and circuit breakers.
7 lessons · about 1.5 hours · Interview Soon · 4 worked case studies
- Consistent Hashing — Core lesson.
- Scaling Reads vs Writes — Core lesson.
- Service Architecture Deep Dive — Depth lesson.
- Design Twitter Feed — Core lesson, worked case study, about 60 minutes, asked at Meta, Twitter.
- Design URL Shortener at Massive Scale — Depth lesson, worked case study, about 60 minutes, asked at Google, Amazon.
- Design Instagram — Depth lesson, worked case study, about 60 minutes, asked at Meta, Pinterest, Snap.
- Design TikTok Feed — Depth lesson, worked case study, about 60 minutes, asked at TikTok, Meta, YouTube.
Raft consensus, distributed locking, saga pattern, and conflict resolution.
9 lessons · about 1.5 hours · Interview Soon · 5 worked case studies
- Consensus & Locking — Core lesson.
- Distributed Transactions — Core lesson.
- Raft Deep Dive — Depth lesson.
- Gossip & Quorum — Depth lesson.
- Design Ticketmaster — Core lesson, worked case study, about 60 minutes, asked at Amazon, Ticketmaster.
- Design Payment System — Core lesson, worked case study, about 60 minutes, asked at Stripe, PayPal.
- Design Ticketmaster at Scale — Depth lesson, worked case study, about 60 minutes, asked at Meta E5.
- Design Google Docs — Depth lesson, worked case study, about 60 minutes, asked at Google, Microsoft, Notion.
- Design a Stock Exchange — Depth lesson, worked case study, about 60 minutes, asked at Jane Street, Citadel, Goldman Sachs.
Full-text search, geospatial indexing, stream processing, and probabilistic structures.
9 lessons · about 1.5 hours · Interview Soon · 5 worked case studies
- Search & Geospatial — Important lesson.
- Real-Time Aggregation — Important lesson.
- Elasticsearch Deep Dive — Depth lesson.
- Probabilistic Structures Deep Dive — Depth lesson.
- Design Uber — Core lesson, worked case study, about 60 minutes, asked at Uber, Lyft.
- Design an Ad Click Aggregator — Depth lesson, worked case study, about 60 minutes, asked at Meta, Google.
- Design Uber Deep Dive — Depth lesson, worked case study, about 60 minutes, asked at Uber.
- Design a Top-K Leaderboard — Depth lesson, worked case study, about 60 minutes, asked at Amazon, Meta, Riot Games.
- Design Google Maps — Depth lesson, worked case study, about 60 minutes, asked at Google, Uber, Apple.
Monitoring, observability, deployment strategies, and graceful degradation.
2 lessons · about 3 hours · Deep Dive
OAuth 2.0, JWT vs sessions, API security, and encryption.
2 lessons · about 3 hours · Deep Dive
LLM serving, inference batching, RAG pipelines, and vector search at scale.
6 lessons · about 6 hours · Deep Dive · 1 worked case study
Deep dives into Discord, Uber, Stripe, Netflix, and Kafka production architectures.
5 lessons · about 4 hours · Deep Dive
26 worked case studies
Each case study takes one product brief through the whole answer — requirements, estimation, API, data model, and the trade-offs an interviewer will push on.
- Design URL Shortener — about 45 minutes, asked at Amazon, Google, Microsoft. Builds on Databases, Caching, Scalability.
- Design Rate Limiter — about 40 minutes, asked at Stripe, Anthropic. Builds on Caching, Scalability.
- Design Twitter Feed — about 45 minutes, asked at Meta, Twitter. Builds on Databases, Caching, Queues & Async.
- Design WhatsApp Chat — about 45 minutes, asked at Meta, WhatsApp. Builds on Networking & APIs, Databases, Queues & Async.
- Design YouTube — about 45 minutes, asked at Google, Netflix. Builds on Databases, Caching, Scalability.
- Design Uber — about 45 minutes, asked at Uber, Lyft. Builds on Search, Geo & Aggregation, Queues & Async, Databases.
- Design Ticketmaster — about 45 minutes, asked at Amazon, Ticketmaster. Builds on Coordination & Transactions, Databases, Caching.
- Design Payment System — about 45 minutes, asked at Stripe, PayPal. Builds on Coordination & Transactions, Queues & Async, Databases.
- Design a Key-Value Store — about 45 minutes, asked at Databricks, Amazon. Builds on Databases, Scalability.
- Design Dropbox — about 45 minutes, asked at Dropbox, Google. Builds on Databases, Queues & Async.
- Design a Distributed Cache — about 45 minutes, asked at Meta E6. Builds on Caching, Scalability.
- Design a Webhook Delivery System — about 45 minutes, asked at Stripe. Builds on Queues & Async, Networking & APIs.
- Design a Notification System — about 45 minutes, asked at Meta, Amazon. Builds on Queues & Async, Scalability.
- Design URL Shortener at Massive Scale — about 45 minutes, asked at Google, Amazon. Builds on Scalability, Search, Geo & Aggregation.
- Design Ticketmaster at Scale — about 45 minutes, asked at Meta E5. Builds on Coordination & Transactions, Scalability.
- Design an Ad Click Aggregator — about 45 minutes, asked at Meta, Google. Builds on Search, Geo & Aggregation, Queues & Async.
- Design Uber Deep Dive — about 45 minutes, asked at Uber. Builds on Search, Geo & Aggregation, Scalability.
- Design a Web Crawler — about 60 minutes, asked at Google, Amazon, Microsoft. Builds on Queues & Async.
- Design a Job Scheduler — about 60 minutes, asked at Airbnb, Uber, Stripe. Builds on Queues & Async.
- Design Instagram — about 60 minutes, asked at Meta, Pinterest, Snap. Builds on Scalability.
- Design TikTok Feed — about 60 minutes, asked at TikTok, Meta, YouTube. Builds on Scalability.
- Design Google Docs — about 60 minutes, asked at Google, Microsoft, Notion. Builds on Coordination & Transactions.
- Design a Stock Exchange — about 60 minutes, asked at Jane Street, Citadel, Goldman Sachs. Builds on Coordination & Transactions.
- Design a Top-K Leaderboard — about 60 minutes, asked at Amazon, Meta, Riot Games. Builds on Search, Geo & Aggregation.
- Design Google Maps — about 60 minutes, asked at Google, Uber, Apple. Builds on Search, Geo & Aggregation.
- Design a Recommendation System — about 60 minutes, asked at Netflix, Amazon, Spotify. Builds on AI Infrastructure.
How to work through the course
Start with the families marked Interview Soon. They cover the decisions that appear in almost every round: the framework for structuring the answer, back-of-the-envelope estimation, the database and caching choices, and the way a design grows under load.
Work a case study straight after the family it belongs to. Reading about consistent hashing and then placing it in a real design is what makes the idea stick, and it rehearses the shape of the conversation you will actually have.
Come back to the Deep Dive families when the interview loop is further out, or when a role names distributed systems, streaming or security explicitly. They go past what a forty-five minute round can reach, and they are what separates a senior answer from a staff one.
Interview Soon families: Foundations, Networking & APIs, Databases, Caching, Queues & Async, Scalability, Coordination & Transactions, Search, Geo & Aggregation. Deep Dive families: Reliability & Operations, Security & Auth, AI Infrastructure, Real-World Architecture Studies.
