Opening your workspace…
Opening your workspace…
Build your system design intuition through small experiments.
Make a prediction, follow the requests, and defend your decision.
Six hundred requests a second. One database. Adding servers sounds reasonable. Follow the evidence and find out.
Explore capacity & cachingFind the bottleneck during a traffic spike, test a warm cache, then challenge the same fix with cold traffic.
Explore the lab02 · FREEUse a token bucket to bound admitted traffic, then distinguish deliberate rejection from serving every request.
Explore the lab03 · PREPARATION PASSCombine workload estimates, cache assumptions and admission control, then defend the remaining design decisions.
Explore the lab04 · PREPARATION PASSAdd a node to a seeded hash ring, inspect key movement, then reveal why a hot key still overloads one owner.
Explore the lab05 · PREPARATION PASSRead behind an asynchronous replica, change the read route, then expose the availability cost of a regional failure.
Explore the lab06 · PREPARATION PASSCompare timestamps alone with coordinated and worker/sequence strategies, then challenge duplicate worker assignment and clock assumptions.
Explore the labContinue through replication, queues, feeds, chat recovery, payment retries, and outage diagnosis. Practice activity describes your work; it does not certify interview readiness.
The diagram is a starting point.
The reasoning is what you take with you.
Commit to an idea before seeing the result. Unsure is a useful place to start.
Change one assumption. Run the model. Inspect the actual event trace.
Use evidence to defend a trade-off, then try a changed requirement.
Animation follows the model. Every result comes from a deterministic simulation with visible assumptions.