Designs by Duhart

Designs by Duhart · work inventory

Thirty-four projects, ranked

Scored on how much real distributed-systems engineering each one carries, not on how impressive it looks.

The rubric, weight × rating, max 120

Canonical DS primitives ×5Partitioning, event logs, idempotency, fan-out, backpressure
Production evidence ×4Deployed, measured, runbooked, failure modes named
Concurrency correctness ×4Races found, fixed, and tested for
Scale artifacts ×3Shard keys, consumer groups, TTLs, hot keys
Language fit ×3Go, Java, Python, C++
Contract discipline ×2OpenAPI / AsyncAPI / protobuf, CI-enforced
Written communication ×2Design docs stating trade-offs and costs
Frontend / mobile ×1Real work; not what this role hires on

Each project is rated 0–5 per signal. Ratings are a hiring judgment, not a measurement, treat differences under about five points as ties.

Tier S

95+

The core distributed-systems work.

1Billboard Activity GraphGo · outbox → Kafka → three consumer groups1032GlobalChat Realtime MessagingGo · Cassandra, Redis, Kafka, WebSocket1063Match Service, Distributed RankingGo · geo-partitioned Cassandra, Redis Streams101

Within 5 points of 120, and that is noise. GlobalChat edges the rubric on production evidence and breadth. The Activity Graph leads anyway because it is the canonical systems-design question with every trade-off already written down. Open with it; bring GlobalChat as proof you have carried something this size in production.

Tier A

75–94

Strong support, infrastructure, ML platform, media.

4Solomon, Serving, Kubernetes & AutoscalingPython · k3s, Helm, HPA, continuous batching905Solomon, LLM Platform (umbrella)The whole pipeline, end to end896FeedBench, One Contract, Three RuntimesWorkers vs Go vs Spring · load ramp + six faults897Production Incidents, Root-CausedKafka offset skip, token reuse, mmap rewrite, OOM878Billboard Production HardeningTypeScript · RS256, 9 tables, CI contract gates849WebRTC Calling PlaneGo · ICE/STUN/TURN, a fatal map race located8310BillboardML, Audio Recognition & RecommendationPython · 457M-pair fingerprint index, gated models8311Storefront Money Spine & Connect PayoutsGo + TS · insert-then-process webhooks, Stripe Connect8112Media & Upload InfrastructureGo + TS · R2 multipart, IngestDO, TUS8013Push & Notification PipelineGo · Kafka → APNs + PushKit VoIP7914Global Feed GatewayTypeScript · D1 Worker, one projection, 244 tests7815Solomon, Retrieval & Agent TierGo · index, agent loop, grounding guard75

Tier B

60–74

Real systems work, narrower in scope.

16Platform Operations & CI/CDsystemd, Compose, two CI systems, six gates7317Billboard Library Sync & The One 100 ChartsTS · last-write-wins + tombstones; a chart over a log7218Auth & Identity PlatformGo · gRPC/Connect, RS256, 24 protobufs7019GlobalChat Messaging UISwift + React · transport/store/runtime split7020Realtime Gateway TrioGo · 48,582 lines over Kafka + Cassandra6921Cloudflare Edge PlatformTypeScript · 10 Workers, D1/R2/KV/DO6822Solomon, Evaluation Gates & PromotionNine release-blocking gates6523Portfolio Platform on WorkersTS · OpenNext Worker, D1, R2, at-least-once queue6424Solomon, Training & Experiment TrackingMLflow, SHA256 manifests, val PPL 40.06325Dating Swipe Deck & Discovery UISwift · 90,161 lines; 49 audited findings6226BoxOffice & the Moderator ConsoleSwift + Next.js · statutory-deadline operator UI61

Tier C

under 60

Breadth and depth-of-craft. Mention, don’t lead.

27OpenHouse GlobalTypeScript · 7 forward-only CQL migrations5728Billboard Player, Audio UI & EngineSwift · actor-isolated AVPlayer, vDSP FFT5629Palantir J8, Exhibit FactoryPython + React · fail-closed financial ingest5530Multiplatform Clients (umbrella)611K lines Swift, 19-module Compose port5431Solomon, The TransformerPyTorch from the paper; KV cache proven equal5332Web Platform UINext.js · every mode, generated protobuf clients5133Solomon, Corpus, Tokenizer & Data Governance130M tokens, 0 UNK, contamination checks4634Technical Documentation CorpusThree 17–20 chapter manuals with gap registers39

Reading paths

Google1 → 3 → 4 → 11
Spotify1 → 21 → 8 → 6
Bank2 → 12 → 16 → 11

Supporting documents

Résumé bulletsPre-sorted by employer, with quotable numbers.The full index documentThe source inventory in long form.