Sangmin Lee
Search Visibility Engineer. Coding since 1996. Founder of RankLabs. Writes engineering notes on JSON-LD, @graph architecture, and AI search readiness.
The arc
I started coding in 1996, age 12, picking up Visual Basicwhile sitting in on my father’s MIS coursework during his MBA. JavaScript followed around 1998. The engineering DNA isn’t a pivot. It’s the foundation.
In 2008 I co-founded an IT consulting company with a college buddy and ran it for nearly seven years. The company pulled me away from full-time production code into stakeholder work, MVP scoping, Agile/SCRUM delivery, and release management. I picked up a masters in computer science in the middle of it. By the time we wound the company down in 2015, I was hungry to be back in the codebase full-time.
That’s the year I joined Complex Networks, a top-tier US digital media publisher. Partnered with their BI team across the sister-site portfolio (millions of monthly visitors per site), led the frontend revamp on three sister sites single-handedly before they consolidated into one platform. That’s where I learned what classic Google organic SEO actually looks like at publisher scale: schema, crawl-budget, internal linking, page speed, ranking signals. A decade before AI search was a category.
After Complex I spent five years deep in full-stack at Verdocs (e-signature platform, library-first architecture, framework-agnostic embeds). Then four-plus years as a Senior Research Scientist at Perspecta Labs (which became Peraton Labs after the 2021 acquisition), building Cesium-based 3D geospatial visualization for federal contracts. Compliance-heavy environments. Real engineering rigor.
I founded Mindcraftor in 2025 (AI SaaS for idea generation, scaled to early adoption then shut at zero MRR, a useful failure). I founded RankLabs later in 2025 because every existing tool in the AI visibility space was a marketer’s tool. They didn’t extract @graph the way AI engines parse it. So I built the infrastructure I wished existed, and now every client engagement I deliver runs through it.
I currently consult through SAE.SO on two parallel tracks: ongoing A/B testing / experimentation work for a Fortune-1000 health & wellness brand (300+ tests and counting since 2021), and a senior full-stack engagement on a separate end-client (2026-02 onwards). The experimentation muscle stays current. I’m still shipping CRO/MVT in production every week.
The Search Visibility Engineering practice is my primary independent practice outside SAE.SO. I take a small number of engagements per quarter(currently 4). US brands, mid-market and Fortune-1000 tier. Both SEO and AEO. I don’t take on engagements I can’t ship myself.
Where the work happened
Founder · RankLabs
AI visibility infrastructure: proprietary crawler, structured-data extraction, page-level scoring, AI engine emulation, field-level schema validation.
Used in every client engagement as the diagnostic backbone. Several capabilities don't exist in incumbent tools (Screaming Frog, Botify, Sitebulb, Onely).
Co-Founder · Senior Full-Stack · Mindcraftor
AI SaaS for idea generation, validation, and autonomous CX workflows. Built with Next.js, Node, Supabase, Stripe, RAG-style flows.
Scaled to early adoption then shut at zero MRR. Useful failure.
Senior Frontend Engineer (Consultant) · SAE.SO
Long-running consultancy contract. 300+ client-side experiments delivered (and counting) for a Fortune-1000 health & wellness enterprise. A/B testing infrastructure ongoing. Concurrent senior full-stack engagement on a separate end-client (2026-02 onwards).
Five years and counting in production CRO/MVT. The experimentation muscle stays current.
Senior Research Scientist · Perspecta Labs / Peraton Labs
Started as Perspecta Labs; renamed Peraton Labs after the 2021 acquisition. Cesium-based 3D geospatial visualization for federal/compliance-heavy environments. Frontend modernization with lazy-loaded modules, modular libraries, state management.
Cut Cesium app load times by ~38% with Web Workers + 2D fallback. Mentored juniors. Set frontend standards across multi-million-dollar contracts.
Senior Full-Stack Engineer · Verdocs
E-signature platform. Pioneered library-first architecture: modularized e-signature flows into reusable libraries. Framework-agnostic embeds (Web Components / Angular custom elements). Mentored devs on scalable UI practices.
Lead Front-End Developer · Complex Networks
Top-tier US digital media publisher. Led frontend revamp on three sister sites single-handedly before consolidation. Partnered with BI team on cross-site technical SEO and conversion experimentation. High-traffic publisher SEO at scale.
Origin of the technical SEO credential, a decade before AI search was a category.
Co-Founder / IT Consultant · Computer Pathways
Co-founded with a college buddy. 6 years 9 months. Worked closely with business stakeholders to direct technology development across multiple enterprise teams: MVP scoping with backlog alignment, Agile/SCRUM delivery via JIRA, release management through demos, technical guides, and training. Translated complex technical content into stakeholder-readable form. Earned a masters in computer science in the middle of the run.
Articles by this author
- // 2026-05-02AI 答案引擎到底是怎麼解析您的 @graph 的
ChatGPT、Perplexity、Claude、Gemini 與 Google AI Overviews 解析 JSON-LD 的方式各不相同。差別很重要。這是我把同一份 @graph 跑過五個引擎之後測到的。
Read the article → - // 2026-05-02我在每一份 commerce 診斷裡都會找到的 10 個 JSON-LD bug(以及它們要您多少錢)
在 4 萬 5 千頁以上的 PDP 目錄裡悄悄失敗的欄位層 JSON-LD bug。每一個都映射到它幹掉的豐富結果、把您從中踢出的 AI 引擎,以及我為客戶建模的美元成本。
Read the article → - // 2026-05-02Schema 會衰減。這是我測出來的半衰期。
生產環境的 Schema 會在沒有任何明顯失敗的情況下,悄悄從 AI 引擎裡消失。這是我跨多個客戶合作測出來的回歸時間線,以及為什麼 CI 驗證關卡不是可選項。
Read the article →
Stop pouring budget into a broken foundation.
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