Design Netflix Open Connect (Streaming CDN)
Netflix's purpose-built CDN serving 200M+ users. Tests bitrate adaptation, edge placement, manifest design, and capacity planning. Open-ended senior-loop favorite.
Org-scope IC. Heavy on architecture, multi-team strategy, technical writing, org influence. Coding rounds emphasize judgment over LC tricks.
Primary categories: system-design · managerial · behavioral
Netflix's purpose-built CDN serving 200M+ users. Tests bitrate adaptation, edge placement, manifest design, and capacity planning. Open-ended senior-loop favorite.
Inventory tracking, robotics control, picking/packing optimization, order routing. Tests cyber-physical workflow design + real-time coordination at warehouse scale.
Apple ICT3+ canonical system design. Tests asymmetric crypto, multi-device key fan-out, offline delivery, and the privacy-first architecture Apple grades senior candidates on.
Amazon's signature L5+ system design. Tests consistent hashing, replication, quorum, vector clocks, and the CAP trade-offs Amazon engineers grade for keenly. Based on the 2007 Dynamo paper.
URL frontier, politeness/rate limiting, dedup via hashing, distributed crawling, robots.txt. Signature Google SDI.
Prototypical Google SDI. Video upload, encoding pipeline, CDN, view counts, recommendations, comments.
Candidate generation → ranking → re-ranking pipeline. Feature stores, A/B testing, real-time inference. Amazon signature SDI.
Geospatial DB, map tile serving, routing with Dijkstra/A*, real-time traffic, Street View tile pyramid.
Trie at scale, top-K ranking per prefix, freshness, multi-language. Most-asked Google + Amazon SDI.
Live video at scale + concurrent comments. Tests RTMP ingest + HLS/LL-HLS distribution + WebSocket fan-out.
Encoding pipeline, CDN, adaptive bitrate, viewing-state durability. Same primitives as Netflix Open Connect plus stricter DRM (PlayReady/Widevine/FairPlay).
Single-threaded event loop, RDB+AOF persistence, replication, cluster mode. Meta E6+ infra round.
Saga pattern across cart → payment → inventory → fulfillment. Tests distributed-transaction handling without 2PC.
Relational + NoSQL hybrid, OLTP vs OLAP separation, global tables. Tests data-modeling decisions at multi-region scale.
Catalog + search + cart + order + payment + inventory + fulfillment decomposed into services. The "draw the whole company" architecture round.
Email storage, search/indexing, spam filtering, threading. Tests inverted indexes + storage tiering.
BLE crowdsourced location, on-device crypto, anti-stalking, lost mode, battery-aware. Apple-specific signature SDI.
WebRTC, signaling, TURN/STUN, recording. Real-time low-latency media.
Channels + persistent chat + presence + voice/video + meetings. Microsoft's most-asked SDI.
Cross-device sync, conflict resolution, on-device + cloud, privacy-preserving. Apple signature SDI.
Project model, language services, autocomplete, debugger plumbing. Microsoft-specific architecture round.
Token management, fan-out, delivery, priority. Foundation of iOS notifications.
Vehicle → edge → cloud, sensor data compression, Kafka/Pulsar, hot/cold tiering, retraining loop.
Triton Inference Server, dynamic batching, KV-cache management, tensor parallelism, paged attention.
Delta updates, staged rollout, canary, rollback, fail-safe, low-bandwidth, fleet segmentation.
GPU performance is bound by memory bandwidth. Shared memory + coalesced global access are the two highest-leverage CUDA optimizations. Required depth at NVIDIA and Tesla Autopilot.
Auto-labeling, shadow mode, rare-event mining, training data curation, reprocessing.
Per-title encoding, per-shot encoding, AV1, codec ladder, GPU-accelerated encoding, cost optimization.
Encoding pipeline → multi-bitrate manifest → Open Connect CDN → ABR playback → resume, sub-2s start, 99.99% availability.
Google L4+ favorite. Tests append-only event ingestion, time-partitioned storage, materialized views for "Continue Watching," and read-time aggregations under privacy constraints.
Master + chunkservers, replication, append-only writes, fault recovery. Foundation of modern data infra.
End-to-end encryption (Signal protocol), message delivery guarantees, group chat, read receipts, multi-device. Meta signature SDI.
Token bucket, sliding window, Redis-backed. Asked at Meta E5+, Amazon, Stripe, Cloudflare.
Catalog, search, payments, review system, distribution at scale, regional availability.
Tensor + pipeline + data parallelism, NCCL all-reduce, FP8/BF16, ZeRO/FSDP, checkpointing. NVIDIA signature SDI.
Real-time station availability, load balancing of grid power, reservations, in-car nav integration, dynamic pricing.
Real-time tracking, maintenance scheduling, route optimization, dispatch. Robotaxi vision system.
Per-profile row construction, ranking, freshness, real-time signal incorporation. 2025 Netflix-reported prompt.
Classic system-design starter. Tests capacity estimation, ID generation, read-heavy storage, caching, and analytics. Asked at Amazon, Microsoft, Uber, LinkedIn.
Meta's E5+ Product Design canon. Push (fan-out-on-write) vs Pull (fan-out-on-read) vs hybrid. The interviewer wants the trade-off math, not a buzzword tour.
Consistent hashing, mcrouter routing, gutter pool, lease tokens. Meta E6+ infra design signature.
IoT device fleet, offline resilience, locker assignment, scanning, security/audit. Tests edge architecture + correctness under intermittent connectivity.
File chunking, dedup, sync, version history, sharing/permissions. Classic SDI asked at all Mag7.
Photo upload + feed + stories + search/explore + hashtags. E5+ Meta product-design canon.
Partitioning, ISR, leader election, consumer groups. Meta E6+ infra signature.
VM allocation, bin packing, fault domains, SLA-aware. Microsoft signature systems SDI.
Bin packing, MIG slicing, gang scheduling, K8s GPU operator, preemption, QoS. NVIDIA signature SDI.
Checkpointing cadence, replica resurrection, NCCL recovery, elastic training. Survival in long-running jobs.
Vehicle → edge → cloud, millions of vehicles, sensor data compression, hot/cold tiering, anomaly detection. Tesla #1 SDI.
Offline candidate generation + online ranking, "row-of-rows" homepage, A/B testing infra, personalization signals.
Structured story format used by every Mag7 behavioral round. Google extends to STAR-L (Learnings). Amazon expects 1 LP per story. Netflix tunes to culture pillars.