SYSTEM DESIGN FOR WORKING DEVELOPERS
Know the pattern.
Explain the decision.
Learn how requests move through a system. Use diagrams to compare design choices and explain failure recovery.
A good diagram shows the flow.
A good explanation shows the tradeoff.
Follow the request.
Understand the tradeoff.
Find the failure mode.
Practice your answer.
THE FREE LIBRARY
See the system. Explain the design.
Read the system diagram.
Trace the request and its recovery.
Caching
Faster reads come with a consistency question. Know when the trade is worth it.
Read the design guide →Message queues
Move work out of the request. Then handle retries, duplicates, and growing backlogs.
Read the design guide →Rate limiting
Protect capacity without punishing normal users. Pick a policy you can defend.
Read the design guide →Safe payment retries
Recover a payment after a server failure. Use a stable key to prevent duplicate charges.
Read the design guide →THE NEXT CHAPTER
A field guide
you’ll actually revisit.
A larger collection of original decision cards, worked designs, and revision drills is in development. These four lessons are the first preview.
Tell me what you need ↗System Design
Decision Cards
- 12 foundational patterns
- 3 complete worked designs
- Printable visual revision cards
- Failure scenarios and interview drills
Scope may evolve with reader feedback. No paid edition is available yet.
Original notes. Inspectable sources.
Written and maintained by Sumit Sawant. Each lesson links to primary technical references. These are learning examples; real architectures depend on your requirements.