Han Tang Lin · backend engineer in Taipei · former astronomer

• 🧑‍💻 Backend Supervisor at Pacston: technical lead on a FastAPI + PostgreSQL platform I architected end to end, leading a backend team of five
• 🔭 Previously an observational astronomer with two first-author papers, on M-dwarf stellar flares (AJ) and Type Ia supernova hosts (MNRAS)
• 🐛 Most useful where a live system is quietly wrong under concurrency: jobs that run three times, locks that aren't there, retries that multiply traffic, tokens nobody verifies
• 🎨 Off-hours: GLSL shaders, React Three Fiber and Blender models, all on my site
• 🌏 中文 · English · Français · 日本語

• 📈 1M+ requests / month across 195 REST endpoints over 44 tables; I wrote ~90% of its 44K production lines
• 🚀 p99 39.2 s → 1.0 s: moved a 37-second reconciliation off the request path behind a Postgres advisory lock; slow requests 880 → 19 per day
• 🔁 3× → exactly once: traced a triple-firing scheduled job to a trigger timeout colliding with AWS async retries
• 🌊 418× retry amplification shut down: 43K requests were fanning out into 18M Lambda invocations
• 🔍 N+1 hunting: 1,108 → 6 queries per request (12.3 s → 775 ms) and 244 → 3 (2.6 s → 210 ms) on core endpoints; primary API mean duration −48%, cold-start init −23%

• 🔭 NCU TOM: target & observation manager in production at Lulin Observatory, built solo (FastAPI, PostgreSQL, Next.js). Rebuilt its light-curve plotting on canvas after benchmarking 15 charting libraries: DOM nodes 60,082 → 104 at 20k points · issue tracker
• ⚖️ sync-async-k8s-path: FastAPI sync vs async measured under Locust load, from CPU-pinned Docker Compose to Kubernetes. Async 512 vs sync 335 RPS, a connection-pool sweep from 167 to 642 RPS, and the single-pod breaking point at 5,000 users · interactive walkthrough
• 🤖 tylerastro.dev: my trilingual notebook for code, life and 推し活, with Tyler-bot, a streaming chat assistant on the Vercel AI SDK checked by an 80+ case pytest eval suite
• 🎤 Utano Track: 15,000+ fan timestamps from VTuber streams, turned into a clickable song index
• 🎶 Let's Sing Together: YouTube playback synced line by line to lyrics, for learning Japanese by singing along
• 🗺️ Folium Institute Map: the QS top-100 physics & astronomy institutes on one interactive world map
• 🛰️ Astronomy-FITS-examples: tools and demos for downloading science images from observatories

• ✨ Simultaneous Detection of Optical Flares of the Magnetically Active M-dwarf Wolf359, AJ 163, 164 (2022), my M.Sc. thesis
• 💥 A closer look at the host-galaxy environment of high-velocity Type Ia supernovae, MNRAS 531, 1988 (2024)

Backend · Python · FastAPI · Django · SQLAlchemy · Pydantic · AWS Chalice
Data · PostgreSQL · MySQL · DynamoDB · Elasticsearch
AWS · Lambda · API Gateway (REST & WebSockets) · Cognito · EventBridge · App Runner · Aurora · CloudWatch
Frontend · TypeScript · Next.js · React · React Three Fiber · Three.js
Tooling · Docker · GitHub Actions · uv · ruff · pytest · OpenAI & Anthropic APIs

• ⚾ Catcher in baseball, outfielder in softball
• 🎤 推し: 白玖ウタノ. Utano Track and her 3rd-anniversary site are my fan projects
• 🎮 Little Busters! and 📺 Angel Beats!, so Key soundtracks on repeat. "My Soul, Your Beats!" forever

🌐 tylerastro.dev · 💼 LinkedIn · ✍️ Medium · ✉️ tyler@tylerastro.dev · 📄 CV