Sangmin Lee
Full-Stack AI Product and Platform Engineer. Writes about product systems, frontend architecture, structured data, and reliable AI-assisted engineering.
The arc
I am a full-stack AI product and platform engineer with 17+ years across software engineering and technology delivery, including 10+ years in senior hands-on production roles. I ship products end to end, then turn repeated complexity into reusable architecture, tooling, and standards.
The career started with stakeholder-facing technology delivery at Computer Pathways, followed by high-traffic frontend work at Complex Networks. I independently revamped three media properties serving millions of monthly visitors each and worked with BI, design, CRO, and product partners on performance and conversion systems.
At Verdocs, I extracted e-signature flows into versioned libraries and exposed framework-agnostic Web Components through stable APIs. At Peraton Labs, I modernized federal research interfaces, established reusable frontend conventions across teams, and improved high-fidelity visualization performance by approximately 38%.
Through SAE.SO, I work across design collaboration, component systems, and experimentation. I have delivered more than 500 A/B and multivariate experiments. On an anonymized e-commerce engagement, a product-template and technical-SEO upgrade increased organic traffic 17%, improved brand visibility across tracked LLMs 43%, and grew AI referral share from 0.1% to 8% of external human sessions.
More recently, I took four products from zero to one across frontend, services, data, deployment, testing, and operations. That work includes RankLabs, Mindcraftor, RecoverPay, and OpenSquid, open-source MIT tooling for deterministic, reviewable coding-agent workflows.
The work shows Staff-level scope through end-to-end product ownership, cross-team architecture and standards, reusable platform adoption, direct client delivery, and mentoring. I am focused on Senior, Staff, and Principal roles where full-stack ownership, frontend-platform depth, and AI-native engineering reinforce each other.
Where the work happened
Independent
Founder & Full-Stack AI Product Engineer
Created OpenSquid, RankLabs, Mindcraftor, and RecoverPay across UI, APIs, data, deployment, testing, and operations. OpenSquid is open-source MIT developer tooling spanning an npm package, CLI, MCP runtime, coding-agent integrations, durable context, and verification gates.
RankLabs operates at <10 ms p95 and improved AI mention coverage 2–4×. Mindcraftor reached 1,600+ users with paid conversions.
SAE.SO
Full-Stack & Experimentation Engineer (Contract)
Worked directly with enterprise client stakeholders in every project meeting during a roughly 3.5-month engagement, translating requirements into implementation decisions. Built roughly half of the client's atomic component library with Tailwind theming, Storybook, automated tests, and accessibility standards; also built experimentation instrumentation adopted across teams.
An anonymized e-commerce template upgrade increased organic traffic 17% and tracked LLM visibility 43% within two months; AI referral share grew from 0.1% to 8% of external human sessions.
Perspecta Labs / Peraton Labs
Senior Research Scientist
Moved research prototypes into production for federal programs, introduced reusable UI libraries and modular conventions, and optimized Cesium-based 3D applications with Web Workers, parallel compute, lazy loading, and 2D fallback.
Delivered approximately 38% faster high-fidelity visualization, established engineering standards, and mentored engineers across programs with tens of millions of dollars in awarded contracts.
Verdocs
Senior Full-Stack Engineer
Extracted complex e-signature flows into standalone, versioned libraries consumed by multiple applications. Exposed framework-agnostic Web Components through Angular custom elements and stable APIs.
Provided an incremental migration path across JavaScript frameworks, reduced duplicate implementation, and coached engineers on maintainable application structure.
Complex Networks
Lead Front-End Developer
Independently revamped three sister sites at a top-tier digital media publisher, each serving millions of monthly visitors, before consolidation into one platform.
Worked with BI, design, CRO, and product partners on performance and conversion systems; defined coding standards and mentored engineers.
Computer Pathways
Co-Founder / IT Consultant
Scoped MVPs with business stakeholders, shaped roadmaps and backlogs, directed technology delivery, led Agile/Scrum releases, and produced technical guides and training.
Built the stakeholder, delivery, and cross-functional judgment that later informed hands-on product and platform leadership.
Articles by this author
- // 2026-08-04After 500+ A/B tests, I started testing the interface no human sees
AI visibility depends on a second interface assembled by crawlers, answer engines, and agents. I call it the shadow interface, and propose a testable funnel for evaluating it.
Read the article → - // 2026-05-02How AI answer engines actually resolve your @graph
ChatGPT, Perplexity, Claude, Gemini, and Google AI Overviews each parse JSON-LD differently. The deltas matter. Here's what I've measured running the same @graph through all five.
Read the article → - // 2026-05-0210 JSON-LD bugs I find in every commerce audit (and what they cost)
Field-level JSON-LD bugs that fail silently across 45K+ PDP catalogs. Each one mapped to the rich result it kills, the AI engine that drops you, and the dollar cost I model for clients.
Read the article → - // 2026-05-02Schema decays. Here's the half-life I've measured.
Production schema goes invisible to AI engines on its own, with no obvious failure. Here's the regression timeline I've measured across client engagements, and why CI gates aren't optional.
Read the article →
Looking for an engineer who can own the product and strengthen the platform?
I am considering Senior, Staff, and Principal roles where I can ship across the stack, improve the frontend platform, and build reliable AI-assisted engineering systems.
direct email · no scheduling gate