GET /hld · building in public
A structured course on high-level and low-level design — taught the way I'd answer in a real interview. Every problem walks the same six-step framework, so the approach becomes muscle memory before the whiteboard does.
The six-step framework, why it exists, and how to practice with it.
read the lesson → step 01What the system must do. Scope ruthlessly — interviews are won here.
read the lesson →Scale, latency, availability, consistency. The numbers that shape every choice after.
coming soonThe nouns of the system — the data model everything else hangs off.
coming soonContracts between components. Endpoints, payloads, and idempotency.
coming soonThe boxes-and-arrows diagram — services, queues, caches, and data flow.
coming soonBottlenecks, failure modes, and trade-offs. Where senior signals live.
coming soonProblem 01 — Distributed Logging System
Kafka, Elasticsearch, S3, Redis, and SSE — the full six-step walkthrough.
new lessons ship as they're written — no schedule, no filler.