# Stefan Rusek **Principal engineer. I build systems — and systems that build systems.** - Email: stefan@rusek.org - GitHub: https://github.com/stefanrusek - LinkedIn: https://www.linkedin.com/in/stefanrusek - Location: South Carolina, USA · Remote - Machine-readable index: [llms.txt](llms.txt) · Evidence: [portfolio.md](portfolio.md) ## Summary Twenty years of shipping — a production compiler at Fog Creek, a three-continent 80-server network at Cheezburger, marketplace platforms at Updater and TaskRabbit. Since February 2026 I have operated in a different gear: I design and run **dark factories** — multi-agent AI orchestration frameworks of my own construction that turn rigorous specifications into tested, production-grade software while I sleep. The output is held to a bar most human teams don't attempt: 100% enforced test coverage, formal invariants, generated-from-code API contracts, spec-first development under a written engineering constitution. The receipts are in git. **Verified highlights** (all figures measured against git on 2026-07-12; methodology in [portfolio.md](portfolio.md)): - ~108K-LOC production platform (TypeScript + Go + Kafka + Kubernetes) built solo in ~8 weeks — Sugar Maple - ~67K-LOC parental-control system with 100% enforced coverage built in a single weekend — family-time - 98% of Sugar Maple's merged commits carry AI co-author trailers — by design - 300K+ MAU on a donation-funded app operated since 2010 - Two competing AI orchestration frameworks, benchmarked against each other with pre-registered experiments ## How I work - **Dark factory orchestration.** Two competing multi-agent frameworks I built and benchmark against each other — three-tier test harness, per-agent-role evals, ground-truth-scored benchmark fixtures, pre-registered A/B experiments with per-dispatch token telemetry. Daily driver since February 2026 (first on Augment Code, rebuilt on Claude Code in April 2026). - **Spec-driven development.** Specification, plan, and task decomposition before code, so agents (and humans) can implement unattended and be gated mechanically. 31 features shipped this way on Sugar Maple alone. - **Trust through gates — at a fraction of the cost.** 100% coverage thresholds, property-based tests, formal invariants, branchless-code doctrine, constitutions enforced by pre-commit hooks — gates that don't care which model wrote the line. So the bulk of implementation runs on Haiku- and Sonnet-class models (97% of Sugar Maple's 739 model-attributed co-author trailers; frontier models are reserved for decomposition, review, and judgment), outrunning big-agents-for-everything approaches on both speed and spend. ## Experience ### Sugar Maple · Sugar Maple Labs, Inc. — Founder & sole engineer (2026–present) Nights-and-weekends venture, building toward first revenue. - Conceived and built a multi-tenant collaborative documentation platform where **AI agents are first-class editors** — an MCP server surface alongside the human web UI, with agent commits attributed via co-author trailers. - ~108K lines across 10 services/apps and 8 shared packages: TypeScript (Fastify, React) services, a Go gRPC git-storage engine, Kafka event choreography, Cloudflare Workers edge auth, WorkOS SSO, Postgres, cdk8s/Tilt Kubernetes — plus OpenTofu IaC promoting through five environments with plan and apply test suites. - Shipped in roughly eight weeks by orchestrating AI agents through 31 spec-driven features under a 22-principle engineering constitution; 98% of merged commits carry AI co-author trailers (~16 agent commits per squash-merged PR). - Quality bar: 100% test-coverage thresholds on every package, OpenAPI contracts generated from code, migrations only via schema tooling, in-cluster E2E suites. - Live proof-of-concept deployment on single-node Kubernetes behind Cloudflare tunnels (zero inbound ports); production AWS/EKS path designed and costed; billing planned post-MVP. Tech: TypeScript · Go · Kafka · gRPC · Kubernetes · Cloudflare Workers · OpenTofu · Postgres · MCP ### TaskRabbit (an IKEA company) — Aug 2024–present **Solutions Architect (Sep 2025–present)** - Re-architected the platform-modernization program: authored the technical plan that unblocked roadmap features stalled for years, and laid the technical foundation and roadmap for fully integrating the TaskRabbit and Dolly businesses. - Daily technical coach and guide to the platform and partnership teams building the new partner platform: 100% backward compatible with both the legacy TaskRabbit API and the Dolly partner API, plus a new, clean unified partner API that books both TaskRabbit in-home services and Dolly delivery — all on a Kafka-driven architecture. - Continual advocate for spec-driven AI development across engineering — the path to AI-written code that scales and can be trusted. **Senior Staff Engineer, Dolly division (Aug 2024–Sep 2025)** - Shipped multi-courier booking — jobs that book more than one courier — on Dolly's 10-service, fully Kafka-driven microservice platform. - Shipped order batching: bundling orders into a batch or route that becomes a single job. - Built a new support-ops tool that dramatically improved the efficiency and usability of daily support operations. - Since March 2026, that platform has accepted only AI-authored, spec-driven commits — a working demonstration of the method at a real company. Tech: TypeScript · Kafka · event-driven microservices · API design · spec-driven AI development ### Updater — Principal Software Engineer (2021–2024; contract 2021–22) - Led two division-wide migrations to Auth0/passwordless authentication — coordinating multiple engineering, product, DevOps, IT, and security teams (40+ people), with real-time automatic user migration, PCI compliance, and customer-facing SSO. - Designed and coordinated the decoupling of six tightly-bound microservices, improving reliability and setting the division's event-driven patterns. - Designed offline-first Android architecture so effective the client cited it as the model for the iOS app. Tech: TypeScript · C# · Ruby · Kotlin · Rust · Go · Terraform · Auth0 ### Ergon Labs — Technical Consultant (2013–2022) - Nine years as a solo consultant and team lead across healthcare, finance, and education — typically working directly with non-technical founders, owning everything from requirements to deployment to maintenance. - Built the first versions of Rover's iOS and Android apps, then trained Rover's own mobile team until they could take over. - Shipped mobile games in Unity, real-time analytics, lead-management and data-sync systems. ### Cheezburger Network — Director of Technology (2011–2013); Lead Software Engineer (2008–2011) - Built and ran a network of 80+ servers in 11 locations on 3 continents, fault-tolerant through simultaneous data-center outages, for one of the era's largest humor publishers. - Managed a fully remote, highly distributed engineering team; built a culture of autonomy for senior engineers and mentorship for everyone. - Built single-step continuous deployment — automated tests plus network-wide deploys, many times a day, in 2011. - As lead engineer: content pipeline, database schema management, unified configuration, monitoring, and an email system sending hundreds of thousands of messages a day. ### Fog Creek Software — Member of Technical Staff (2005–2008) - Owned the compiler for Wasabi, Fog Creek's in-house language — building back-ends targeting the CLR, ASP, PHP, Python, and JavaScript so one codebase shipped everywhere. - Built FogBugz's fast intelligent search and the automated testing system that verified four builds a day. - (Fog Creek is the company that later created Trello and co-founded Stack Overflow.) ## Selected projects See [portfolio.md](portfolio.md) for full case studies and verification commands. - **Dark Factory** — two benchmarked multi-agent AI orchestration frameworks; daily driver since Feb 2026. - **Sugar Maple** — 108K-LOC collaborative docs platform where AI agents are first-class editors; built in 8 weeks. - **family-time** — 67K-LOC parental-control system with 100% coverage; built in a weekend. - **Ο Μαθητής** — 47K-LOC reader for Greek & Latin classics (Perseus corpus), live on the web; the dark factory's first proving ground. - **Unfasten** — hand-written Flutter+Firebase fasting app (https://unfasten.app); 13 releases; daily personal use. - **OI LOGOI** — hand-written reader for ancient Greek NT manuscripts with a round-trip-tested custom parser. - **Rusek Ministries** — daily Bible-study app since 2010; ~300K MAU as of 2024; donation-supported. ## Education & community **B.S. Physics & Computer Science — Middle Tennessee State University (2003–2005).** 3.9 GPA, mathematics minor, Sigma Pi Sigma physics honor society; undergraduate research in photonic band-gap crystals and Bayesian question generation. Earlier coursework at Southern Adventist University, where I taught C# and object-oriented design in the M.S. Software Engineering program. **Community:** school board member 2017–2020 (including a year as interim school director); nonprofit treasurer 2021–2023.