Hi, I’m
Calvin 👋

Co-founder, Head of Growth · XonLabs · 2023 — now

The smarter way to learn with flashcards. Turn lecture slides, PDFs and notes into spaced-repetition decks in minutes, built on active recall. Started as a weekend project in the HKU medical library as PDF2Anki — 100,000 users across 106 countries within a year, 400,000+ today.

Co-founder · 2024 — now

An AI food diary that judges quality, not just calories. Snap a meal, get a nutrition score using the HEI system plus a traffic-light read on veg, fruit and sodium. Built after too many ward rounds meeting patients with entirely preventable type-2 diabetes, hypertension and hyperlipidaemia.

Solo project · 2025

A clean, fast clinical reference written the way medical students actually revise — organised by specialty across internal medicine, surgery, paediatrics, O&G, psychiatry, orthopaedics, family and emergency medicine.