About the Author

Hi, I’m Stan Lee.

I’m a Staff Software Engineer based in Rocklin, California, with over fifteen years of experience building software for Silicon Valley companies — work that has spanned very different layers of the stack, from firmware that runs before the operating system to large-scale web platforms used by real customers every day. My career hasn’t followed a straight line, and that winding path is exactly what shaped how I think about systems.

I started out deep in BIOS and UEFI firmware at Dell, debugging issues across servers, desktops, laptops, storage, and switches. From there I moved into distributed systems, then backend services, and eventually frontend web development — each step bringing me closer to products, users, and impact. Working across every layer taught me to ask not only how a system works, but why it matters.

Today I’m a Staff Software Engineer at BILL in San Jose, where I lead frontend architecture and authentication and identity work for the company’s Spend & Expense product line. Before BILL, I led GraphQL backend and federation work at Rivian, built customer-portal and conversational-AI features at Infinitus Systems, designed authentication systems on AWS Cognito at Kind Health, and spent six years at Dell spanning firmware, hardware bring-up, and web development.

How I think about software

I’ve worked as a backend, frontend, and full-stack engineer, designing APIs, GraphQL platforms (including Federation), distributed systems, and the user-facing applications on top of them. I’ve helped build enterprise-scale products, supported high-stakes launches, and worked across teams with very different constraints — from fast-moving startups to regulated industries.

Along the way I’ve learned that good software engineering is less about chasing trends and more about fundamentals: clear thinking, solid abstractions, and an honest understanding of trade-offs. That bias toward fundamentals is what shaped this site.

Why this site exists

System design interviews ask senior engineers to defend architectural decisions under time pressure — and most of the available material is either too shallow (“here are some buzzwords”) or too sprawling (a 600-page book you’ll never finish). I wanted a study companion that respected the reader’s time: short enough to read in a sitting, dense enough to power a real whiteboard discussion, and opinionated enough to be useful. That’s the bar I held every page on this site to.

If you’re preparing for a system design loop, I hope these notes save you time. If you find something wrong, unclear, or missing, please tell me — system design is a craft, and good craft only improves through feedback.

Where else I write

I also publish at SWENG.dev, where I write longer-form pieces on system design, backend and frontend engineering, architecture decisions, tooling, performance, and the less-discussed parts of the job — career transitions, technical debt, and how engineers grow over time. Lately I’ve also been exploring AI and agent-based systems there: not as a buzzword, but as another set of tools that senior engineers need to understand deeply to use responsibly.

For Korean-speaking readers, I keep a separate blog at StanStory.com.

A few things about me

• Location: Rocklin, CA (USA)
• Education: MS in Computer Science, Yale University · Bachelor in Business Administration, Seoul National University (South Korea) · BS in Electrical Engineering & Computer Science, KAIST (South Korea)
• Tools I reach for most: TypeScript / JavaScript, Go, Node.js, React, Next.js, GraphQL (and Federation), PostgreSQL, MongoDB, DynamoDB, AWS, Kubernetes
• Outside of work: family, piano, guitar, table tennis, and the occasional weekend side project

Get in touch

I’d love to hear from you — feedback on this site, questions about a topic, or just a hello.

• Email: stanley.s.lee@gmail.com
• Personal site: https://stanlee.tech
• Blog: https://sweng.dev
• GitHub: https://github.com/stancs
• LinkedIn: https://www.linkedin.com/in/stanlee-cs

Thanks for stopping by. Hope you find something useful here. 🙏