Course
System design interview prep you can actually check
Learn the building blocks, then draw your architecture on a canvas and submit it. Rules that follow from the requirements tell you what holds up and what falls over.
- 3 topics
- 12 skills
- 48 lessons
- 142 practice questions
- 4 design problems
What you'll learn
Start with how the interview works and how to estimate on the back of an envelope, then the building blocks: load balancers and API gateways, caching, replication and choosing a data store, sharding and consistent hashing, queues and asynchronous processing, and the trade-offs between consistency and availability. Every skill has a lesson, a staff-level deep dive and practice questions.
Then design a URL shortener, a news feed, a chat system and a video streaming service. You place typed components, connect them with sync or async calls, set instance counts and capacity estimates, and note your reasoning. Each design is checked against rules taken from the brief, with an explanation of every failure and a reference design to compare with yours.
The curriculum
Every skill has a lesson, a staff-level deep dive, a quick revise page and practice questions. Click a skill to read its lesson free.
System Design Fundamentals
How a system design interview runs, how to size a system with back-of-the-envelope numbers, and a first complete design - scaling a read-heavy service.
The System Design Interview
Back-of-the-Envelope Estimation
Scalability Basics
Building Blocks
The components every design is assembled from - load balancers, caches, replicated and partitioned databases, message queues - and the consistency trade-offs that come with spreading data across machines.
Load Balancing and API Gateways
Caching
Databases and Replication
Partitioning and Consistent Hashing
Message Queues and Async Processing
Consistency and Availability
Design Problems
Complete designs of well-known systems on the design canvas - a news feed, a chat service and a video platform - each checked against its requirements and failure modes.
News Feed
Chat System
Video Streaming
The design problems
Design problems
- Design a URL ShortenerFree
- Design a Chat SystemPro
- Design a News FeedPro
- Design a Video Streaming ServicePro
Questions
Can a system design answer really be graded automatically?
The decisions can. Each check follows from something the brief says: traffic enters through a load balancer, there's no single point of failure, reads survive a cache outage, a tier has enough capacity for the peak. Equivalent answers are accepted, such as a load balancer or an API gateway. What the checks can't judge is how you explain it, so practice that out loud too.
Is this enough for senior system design interviews?
It covers the building blocks and the reasoning senior loops expect, and the staff-level deep dives go into costs at scale, failure modes and how interviewers probe each topic.
Do I need to know object-oriented design first?
No. System design and object-oriented design are separate courses. Many engineers do both, since senior loops often include both rounds.
What's free in the system design course?
All 48 lessons and 142 practice questions, plus the URL shortener design. Pro unlocks the news feed, chat and video streaming designs.
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