Interview training studio
Code, diagrams, spoken answers, and a company brief. Start with the round you need to practice.
Inside the studio
01 / 04type Tx = { accountId: string; delta: number; ts: number }; export function rebuild(events: Tx[]): Record<string, number> { return events.reduce<Record<string, number>>((acc, ev) => { const current = acc[ev.accountId] ?? 0; acc[ev.accountId] = current + ev.delta; return acc; }, {});}Event-sourced rebuild
Replay from the event log.
Materialize state from event stream. Keep the original transactions immutable.
01Single Account Ledger02Transfers & AtomicityEvent-Sourced Rebuild04Rolling Cashback
Immutable replay coreTypeScript
Interviewer
“Your design works at 100 requests a second. What changes at 10,000?”
You
“I would first separate the latency budget from throughput, then test where queueing starts…”
Microphone offExample transcript
Evidence binder
Browser-local Example source clipping
Engineering interview guidance
Architecture, reliability, and the reasoning behind a design decision.
Reviewed practice linksSketch a systemDefend a design decision
Use this source to prioritize practice
Practice emphasis Sketch a system
Reviewed source links and your own debriefs shape the order.
Public-source collection is not a comprehensive company assessment or a verified interview rubric.
A plan for your next interview.
Set the role, round mix, and time you have. Review company sources and debrief your practice to keep the next session focused.
