Hi, my name is
Nan He (Sam).
I build customer-focused, LLM-powered products.
I'm a software engineer specializing in full-stack development and generative AI, transforming ambiguous business problems into scalable production solutions.
About Me
Hello! I'm Sam, a software engineer based in San Francisco. I specialize in building (and occasionally designing) exceptional digital experiences. My focus is on creating full-stack, LLM-powered products, taking them from initial concept to robust production systems.
With over 7 years in the field, I've had the privilege of working as a founding engineer, collaborating directly with customers to solve complex business challenges. I thrive on rapid prototyping and iterative development, leveraging technologies like OpenAI, React/Next.js, and Python in cloud environments such as AWS and GCP.
Currently, I'm exploring new opportunities where I can contribute to innovative projects and continue to grow my skills in generative AI and cloud architecture. When I'm not coding, I enjoy exploring the Bay Area, trying out new recipes, and keeping up with the latest tech trends.
Here are a few technologies I've been working with recently:
- Python
- FastAPI
- Node.js
- React
- Next.js
- TypeScript
- LangChain
- OpenAI API
- AWS (CDK, Lambda, EC2, DynamoDB)
Where I've Worked
Dec 2023 – Oct 2024
Founding Engineer @ Portal AI
Bay Area, CA
- Embedded with three Fortune‑500 design partners to map business workflows, design PoCs with OpenAI GPT‑4 via LangChain, and iterate to production, enabling one paying pilot and two additional pending contracts.
- Led architecture and hands‑on coding of a secure, three‑account AWS CDK infrastructure and vector‑search backend, moving from zero to production in two weeks.
- Delivered technical collateral alongside Sales and Customer Success, capturing best practices that became the team’s internal playbook.
- Recruited and mentored 7 engineers across US/EU; established onboarding and code‑review processes to maintain velocity as team scaled.
Jun 2022 – Dec 2023
Software Engineer, Vertex AI @ Google Cloud
Bay Area, CA
- Architected AutoSxS‑based framework that automated large‑scale LLM evaluation for customers, reducing benchmarking time by 90 % and surfacing actionable feedback to product teams.
- Built cloud‑resource cleanup toolkit adopted by 5+ partner teams, saving $600k in monthly spend and strengthening governance posture.
- Presented evaluation best‑practices in customer councils and internal brown bags; contributions were incorporated into Vertex AI solution guides.
Jan 2021 – Jun 2022
Software Engineer @ Amazon Alexa Shopping
Bay Area, CA
- Designed data‑access layer for authority database powering voice shopping intents used by 20 M+ devices.
- Instituted BI metric conventions and refactored publishing pipelines, unlocking self‑serve analytics for product managers.
- Facilitated operational readiness reviews with engineering and business stakeholders ahead of Black Friday peak.
Aug 2019 – Jan 2021
Software Engineer @ Amazon EC2
Bay Area, CA
- Prototyped storage‑optimized i4 instance on new hardware, influencing roadmap of high‑IO fleets.
- Shipped dashboards and on‑call automation that cut fleet issue mean‑time‑to‑detect by 35 %.
Things I've Built
Hands‑free baby tracker leveraging Whisper + GPT to convert voice notes into structured logs; Next.js + Supabase backend with Postgres and vector store.
Real‑time co‑watch platform; migrated from Flask to Serverless, cutting cost 90 %.
Other Noteworthy Projects
Get In Touch
I'm currently open to new opportunities and collaborations. Whether you have a question or just want to say hi, feel free to reach out. My inbox is always open!