Build the system. Survive the day.
System design guides
Build a practice habit, follow a two-week plan and learn classic systems through requirements, estimates, trade-offs and failures.
- By System Designer
Build the system. Survive the day. See why it held.
Meet System Designer: a free browser game with 82 system design problems, 41 lessons and a traffic day that puts your decisions to work.
- By System Designer
How to practise system design
A practical loop for turning a diagram into a design you can explain: clarify, estimate, predict a failure, test it and revise one decision.
- By System Designer
A two-week system design interview plan
Fourteen days of lessons, traffic experiments and design explanations, with Interview mode in the second week. Every task links to a real lesson or problem.
- By System Designer
URL shortener walkthrough
Separate durable link storage from fast redirects, estimate the read path and test what happens when a popular link outgrows its cache.
- By System Designer
Rate limiter walkthrough
Build fair admission for a public API: estimate counters, choose a sharing policy and explain what happens when the limiter cannot answer.
- By System Designer
Chat system walkthrough
Design message identity, durable acknowledgement and reconnect behavior before treating chat as a socket-count problem.
- By System Designer
News feed walkthrough
Estimate fanout work, keep posts authoritative and choose where to assemble feeds for ordinary accounts and celebrities.
- By System Designer
Notification service walkthrough
Separate acceptance from sending, respect provider quotas and reason about expiry and unknown outcomes before claiming delivery once.
- By System Designer
Caching, load balancing and queues, explained by breaking things
Three small experiments show what caching, load balancing and queues protect, what they cost and how each can fail.