Zestimer
Native iOS HIIT/interval workout timer with voice cues, haptics, and an AI workout builder.
Peng-Yu Chen
Software Engineer New York
About
Bio
Hi, I'm Peng-Yu Chen, originally from the beautiful island of Penghu in Taiwan.
I build apps for a living and for fun. By day I'm a Software Engineer in NYC; by night I'm shipping side projects and iOS apps, usually chasing whatever idea won't leave me alone.
I care a lot about craft — clean code, thoughtful conventions, and the little details that make software feel just right. It shows up in what I ship: apps that stay minimal and friendly, with nothing to figure out and nothing in your way. Try a few — they are all a click or a download away.
Now
Most of my nights go to Zestimer, an interval timer for iPhone, Apple Watch, and the Home Screen. It talks you through a workout so you never have to look down at your phone.
Give it a try at zestimer.com — and tell me what you would change.
Fun Facts
Wendy's Chicken is my first meal in the US.
C is the first programming language I learned.
I know a little Japanese, mostly picked up from anime.
My cat is named "Lola".
Apps I Wish Exist
zestimer.com
Furioke
Turns songs you already stream into Japanese lessons — synced lyrics, furigana, and flashcards on web, iOS, and Android.
Tefuda
Poker solitaire with a push-your-luck streak — place cards, spend your discards wisely, and stack perks to climb levels.
Zhuangzi
All thirty-three chapters of the 莊子 in classical Chinese and English, with every line linkable — an iPhone app with a web fallback.
Open Source
CLRS Solutions
Solutions to exercises and problems in Introduction to Algorithms (CLRS) — 5K+ stars, 1K+ forks on GitHub.
app-kit
The shared harness behind my apps — one manifest per repo, one command, and a deterministic store-screenshot pipeline for iOS, Android, and web.
LeetCode Solutions
Readable solutions to 3,500+ LeetCode problems in C++, Java, and Python.
Work
Software Engineer
June 2022 - Present
New York, NY
Snap Inc.
Software Engineer
March 2022 - June 2022
New York, NY
- Built messaging infrastructure for a single and consistent logic in C++ to bridge iOS and Android with backend
- Sped up the messaging experience in fetching feed and syncing feed by parallelization for 20% through A/B study
- Implemented GoogleTest to cover 99% of the business logic in both unit testing and integration testing
Meta
Software Engineer Intern
May 2021 - August 2021
New York, NY
- Established GraphQL APIs by Hack and created Python scripts that call the APIs to onboard Jest tests, allowing iOS and Android developers to have a uniform script to onboard newly written Jest tests
- Recommended trial numbers to lower the standard deviation of metric values by over 25% for three Jest tests
- Tinkered new formula for reasonable trial numbers with senior engineers and reported the process in daily standup
Education
New York University
M.S. in Computer Science
2020 - 2021
New York, NY
National Taiwan University
B.S. in Computer Science
2015 - 2018
Taipei, Taiwan