Welcome — Your learning path and how to begin

1.1 — What is system design?

1.2 — The eight key principles

1.3 — Start the whiteboard example

1.4 — Build the architecture

1.5 — Follow the system in action

1.6 — Review the design

Module 1 practice — Design challenge, worked solution & glossary

2.1 — From a requirement to an API

2.2 — Make the contract precise

2.3 — Draw the library data model

2.4 — Follow one borrowing request

2.5 — Improve the design with evidence

2.6 — Review and transfer the method

Module 2 practice — Renew a loan, worked solution & glossary

3.1 — Understand what must scale

3.2 — Estimate traffic and storage

3.3 — Design mappings and short codes

3.4 — Follow creation and redirection

3.5 — Add capacity deliberately

3.6 — Review the design under pressure

Module 3 practice — Campaign spike, worked solution & glossary

4.1 — Decide what a cache is for

4.2 — Draw the read path

4.3 — Make updates and freshness explicit

4.4 — Compare policies with small traces

4.5 — Connect caching to storage and failure

4.6 — Tell the complete pin story

Module 4 practice — Cache challenge, worked solution & glossary

5.1 — Define the promise before the failure

5.2 — Draw a complete upload and download

5.3 — Bound waiting and duplicate work

5.4 — Stop failures from spreading

5.5 — Recover data and authority

5.6 — Tell the recovery story end to end

Module 5 practice — Recovery challenge, worked solution & glossary

6.1 — Define what sending a message promises

6.2 — Draw the smallest complete chat path

6.3 — Preserve work across the delivery gap

6.4 — Handle duplicate, delayed, and offline messages

6.5 — Bound resources and secure the boundaries

6.6 — Tell the complete event story

Module 6 practice — Messaging challenge, worked solution & glossary

7.1 — Start with the viewing experience

7.2 — Prepare Journey before anybody presses Play

7.3 — Draw the control path and the media path

7.4 — Explain buffering and adaptive playback

7.5 — Observe and recover without blocking playback

7.6 — Present the complete Journey design

Module 7 practice — Viewing challenge, worked solution & glossary

8.1 — Define the promise and the experiment

8.2 — Run and inspect the baseline

8.3 — Handle lost responses and repeated events

8.4 — Bound temporary failures

8.5 — Replace teaching boxes responsibly

8.6 — Complete the capstone and explain the evidence

Module 8 practice — C# lab, capstone solution & glossary