System Design Foundations

The plan, week by week

Times are each lesson’s own reading time, added up. A mock interview is set to 45 minutes. A lock means the lesson is in the course.

1. Week 1

   The numbers and the basics

   175 min

   Learn how a system is measured, and the two ways to make it bigger.

   1. LatencySystem Design lesson14 minfree
   2. ThroughputSystem Design lesson10 minfree
   3. BandwidthSystem Design lesson17 minfree
   4. Synchronous ProcessingSystem Design lesson14 minfree
   5. Asynchronous ProcessingSystem Design lesson18 minfree
   6. ScalabilitySystem Design lesson20 minin the course
   7. Vertical ScalingSystem Design lesson20 minin the course
   8. Horizontal ScalingSystem Design lesson32 minin the course
   9. Stateless vs Stateful SystemsSystem Design lesson30 minin the course
2. Week 2

   How traffic finds your servers

   218 min

   Follow one request from a phone to your code and back.

   1. DNS (Domain Name System)System Design lesson40 minfree
   2. Load BalancingSystem Design lesson34 minin the course
   3. Load Balancer AlgorithmsSystem Design lesson30 minin the course
   4. Reverse ProxySystem Design lesson32 minin the course
   5. Content Delivery Network (CDN)System Design lesson26 minin the course
   6. API GatewaySystem Design lesson28 minin the course
   7. REST APISystem Design lesson28 minin the course
3. Week 3

   Where the data lives

   170 min

   Pick a database, make it fast to read, and split it when one machine is not enough.

   1. SQL vs NoSQLSystem Design lesson42 minin the course
   2. Database IndexingSystem Design lesson26 minin the course
   3. ACID PropertiesSystem Design lesson25 minin the course
   4. Database ReplicationSystem Design lesson20 minin the course
   5. Read ReplicasSystem Design lesson22 minin the course
   6. Database ShardingSystem Design lesson35 minin the course
4. Week 4

   Caching

   152 min

   Serve most reads from memory, and keep the copies honest.

   1. CachingSystem Design lesson30 minin the course
   2. Cache Eviction PoliciesSystem Design lesson24 minfree
   3. Time To Live (TTL)System Design lesson24 minfree
   4. Cache InvalidationSystem Design lesson25 minfree
   5. Cache-Aside PatternSystem Design lesson25 minin the course
   6. Distributed Caching with Redis and MemcachedSystem Design lesson24 minfree
5. Milestone

   Design a read-heavy web app

   118 min

   Put the four weeks together on one real system, then defend it out loud.

   milestone: Design a scalable read-heavy web app, like a URL shortener, and defend it in a mock interview.

   1. Design Tiny URL Shortenerinterview guide, free8 minfree
   2. Design a URL ShortenerSystem Design lesson65 minin the course
   3. Mock interview: design Tiny URL ShortenerAI interviewer, junior level45 min

Questions about this path

Do I need a computer science degree for this path?

No. You need to be able to write simple code and call an API. Every lesson starts from a real-life example and defines each new word before it uses it.

How long does the Foundations path take?

Four weeks of reading and one milestone week, at about an hour a day. The time shown on this page is added up from each lesson's own reading time.

What is the milestone at the end?

You design a read-heavy web app, a URL shortener, using the interview guide, then defend your design to the AI tutor in a mock interview. The tutor scores you on ten points and quotes your own answers back to you.

Other paths