Sean Chang

Research Engineer, Google Research · Health AI

seanchang.me
linkedin.com/in/seantc/
New York

Bringing better health answers to everyone. I build the models, safety systems and infrastructure behind health answers at Google. On the side, I'm building Corneo, a skincare routine app.

Core skills

Health AI safety: Classifiers and evaluations that decide when a medical question or answer needs extra care. Safety classifiers · Evaluation · Clinical grounding
LLM systems and agents: Retrieval that grounds answers in search and literature, and memory that lets agents hand off context. RAG · Agent memory · Grounding
Model training and research: Fine-tuning and controlled experiments, from hypothesis to a measured result. Fine-tuning · LoRA / QLoRA · Experiment design
Cloud infrastructure at scale: Production services on GCP and AWS that stay up when real traffic arrives. GCP · AWS · Distributed systems
Products, end to end: Taking an idea to a shipped app on my own: mobile, web and the backend behind them. iOS · Web · Backend

Languages: Python, C++, Java, TypeScript, SQL

Public work at Google

AI Mode in Google SearchProduct · 2025
Search's conversational mode, built on Gemini. I built the query and response classifiers that keep answers about medication dosage safe.
Fitbit Plan for CareProduct · 2025
A Fitbit Labs experiment that helps people prepare for doctor visits. I built its infrastructure and the conversational memory its agents share.
Med-GeminiResearch · 2024
Gemini models adapted for medicine. I studied answers written for consumers, grounded in fast Google Search and medical literature through a retrieval (RAG) harness.

Side project

CorneoiOS app · skincare routines

Builds a routine from the products you already own, then adjusts it as your skin changes. Recommendations lean on evidence, not hype.