Lessons
1Building blocks every round reuses55 min read
Load balancers, caches, sharding, queues, IDs, CDN, search, WebSockets, observability — with reported/heuristic production numbers and a full request lifecycle.
- →Distributed Building Blocks
2The 45–60 min framework + capacity with a why55 min read
Five-step interview OS: clarify, estimate with decision-linked math, API/model, deep dive, wrap — plus L4/L5/L6 bars and anti cargo-cult estimation.
- →System Design Method
- →Decision-Linked Capacity
3Multi-region, multi-tenancy, cost, ops55 min read
Active-active vs passive, silo vs pool, noisy neighbors, cardinality traps, unit cost, deploy/rollback — evolved through a B2B analytics SaaS story.
- →Senior Reliability Layer
4Worked design — URL shortener55 min read
Full shortener: base62/IDs, write and redirect paths, cache, hot aliases, async analytics, and estimation that kills over-engineering or forces edge cache.
- →Distributed Building Blocks
5Worked design — newsfeed at scale55 min read
Fan-out-on-write vs pull, hybrid celebrity tier, timeline materialization, hydration caches, ranking altitude, and cost-per-render levers.
- →Fan-out and Search Systems
- →Decision-Linked Capacity
6Worked design — realtime chat & notifications55 min read
WebSocket gateways, presence, per-channel ordering, multi-device catch-up, push reliability, and message persistence with Discord’s reported production anchors.
- →Realtime and Dispatch Systems
- →Decision-Linked Capacity
7Worked designs — rate limiter + search55 min read
Distributed token buckets without global locks, enforcement layers, inverted indexes, typeahead, async freshness, and ranking altitude.
- →Fan-out and Search Systems
- →Distributed Building Blocks
8Worked design — marketplace/dispatch + mock60 min read
Geo dispatch (H3/S2), atomic matching, ETA/surge, two-sided consistency, fraud altitude, 45-min mock rubric, and pointer to ml-system-design for AI-native rounds.
- →System Design Method
- →Realtime and Dispatch Systems
- →Senior Reliability Layer
Skills in this course
- 01System Design MethodDrive a design from requirements through architecture, deep dives, and operations.
- 02Distributed Building BlocksSelect load balancing, caches, queues, storage, IDs, and consistency from needs.
- 03Decision-Linked CapacityEstimate traffic and storage only where numbers change architecture.
- 04Senior Reliability LayerDesign tenancy, regions, cost, deployment, observability, and recovery.
- 05Fan-out and Search SystemsChoose fan-out, indexing, ranking, and rate control for large read systems.
- 06Realtime and Dispatch SystemsDesign ordered messaging, presence, reconnect, matching, and notification paths.