ai product engineer@id smlee.dev/#person

Sangmin Lee — AI Product Engineer.

I ship LLM products from idea to production.

Applied AI & full-stack. I take LLM products from idea to production — and build the reliability layer that makes them hold up.

four 0→1 builds · Peraton Labs research · engineering since 1996
OPEN TO AI PRODUCT ENGINEER / FDE ROLES
Sangmin's assistantbuilt-in
loopscope⟨gate⟩executeverifyfix
answers from a built-in index — fast, private, runs fully on-device. (The live on-device model, Gemini Nano, needs desktop Chrome.)
01 · selected work

Things I've taken 0→1.

Founder or lead engineer on each.

the flagship · reliability

OpenSquid

The anti-drift framework behind how I ship AI-native software: an MCP server that gates autonomous coding behind hard, blocking quality checks — with a 7-phase workflow ledger and persistent memory on a Rust engine substrate. The gated Ralph loop that keeps agents on-task instead of drifting; the reliability method the other builds run on.

TypeScriptMCPRust
founder · applied AI

RankLabs

2–4×

AI-search visibility engine: continuous monitoring pipelines — controlled LLM querying, crawlers, analytics — that detect model-response drift, competitive displacement, and visibility loss. Drove 2–4× AI mention coverage in controlled deployments.

LLMsNext.jsTypeScriptanalytics
co-founder · applied AI SaaS

Mindcraftor

1,600+

Applied-AI SaaS that generates, validates, and scores business ideas on market, compliance, and feasibility — OpenAI Responses API, multi-stage pipelines, pgvector semantic retrieval. 1,600+ users, validated by paid conversions.

LLMsOpenAI APIpgvectorfull-stack
founder · applied AI

RecoverPay

Pre-transaction fraud detection for SaaS: client-side signals, real-time analytics, and server-side logic that catch velocity spikes and abnormal interaction patterns before downstream processing.

applied AIreal-time analyticsTypeScript
// experience

Where else I shipped

  • SAE.SOSenior Frontend Engineer (Consultant)
    2021-06 – present300+ experiments
  • Perspecta Labs / Peraton LabsSenior Research Scientist
    2021-01 – 2025-05 · 4 yrs~38% faster load
  • VerdocsSenior Full-Stack Engineer
    2016-12 – 2021-01 · 5 yrslibrary-first e-signature platform
  • Complex NetworksLead Front-End Developer
    2015-09 – 2016-12 · 1 yrfrontend at publisher scale
  • Computer PathwaysCo-Founder / IT Consultant
    2008-07 – 2015-03 · 7 yrsco-founded IT consultancy
field notes

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field notes from building LLM products
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03 · work with me

Ways to work together.

Three ways to bring me in, matched to where you are.

  • Full-timeopen to the right role

    Join your team as an AI Product Engineer

    Embedded on the team, shipping LLM products from idea to production — with the full-stack rigor to keep them working once real users arrive.

  • Contractlimited project slots

    Ship a 0→1 LLM product on a fixed engagement

    A scoped build, idea to production, by an engineer who has taken four products 0→1. One clear deliverable, one clear timeline.

  • Advisory

    Advise on agentic / AI-native architecture

    Reliability layer, anti-drift, evals, and workflow design — the parts that decide whether an agentic system is trustworthy enough to ship.

05contact

Building something that has to hold up?

If you're shipping an LLM product — or you need the reliability layer that keeps one working in production — that's the work I do. The fastest way to reach me is right here.

engineer to engineer — no recruiters, no decks
or write me directly
I read every message. Reply within 24h.// legitimate interest (GDPR Art. 6(1)(f)) — you requested the contact. privacy policy