Justin D'Souza
About Me
Hey! I'm Justin. I'm a Software Engineer based in New York City. I studied Computer Engineering at the University of Waterloo.
My childhood was a bit unusual. I was born in Canada, but spent most of my early years abroad in different pockets of Asia (Hong Kong, India, and the Philippines). I later returned north for school and eventually settled in the U.S.
Career
I've spent ~7 years architecting large‑scale ML systems end to end and have ridden the startup roller‑coaster a few times:
- Caffeine TV: Designed multi‑armed bandit algorithms serving millions of personalized creator recommendations daily.
- Level: Built a real‑time fraud detection system processing 100K+ credit‑card transactions per day and led a team of 6 to re-architect Level's purchase processing engine.
- Doppel (current): I lead ML platform initiatives and designed the core cybersecurity threat‑detection ML systems which scan 100M+ entities per day; recognized as top Eng performer in org for foundational contributions to Doppel's data/ML platform.
Selected Talks
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Using LLMs to combat social engineering in real-time (2025)
Technical webinar showcasing how Doppel leverages Chalk's feature platform to power our feature serving pipelines. Event details.
Journey Highlights
2018
First data science intern at Quandl, a leading provider of alternative data. I loved it so much I restructured my college program to extend my time there. Learned a ton about building and selling data products from scratch.
2019
First non‑Ivy League quant‑research intern at a hedge fund in Connecticut — worked alongside some of the sharpest minds I've met. Did deep learning research for alpha generation in a pre-transformer era.
2020
Joined Level, then left after ~9 months to join a world-class data team at Caffeine.
2021
My timing wasn't great and Caffeine had org-wide layoffs (and later shut down); returned to Level and learned I tend to overestimate risks.
2022
Tore my meniscus playing soccer, then spent a month solo‑traveling across Europe.
2023
Met some of the best friends of my life, and made my first end-of-year highlight reel video (and have kept the tradition ever since)!
2024
After helping scale Level for nearly four years, I left to join friends at Doppel as an early engineer; Level shut down months later.
2025
TBD =)
Hobbies
- Competing in Hyrox fitness races.
- Running (1:47 half marathon PR).
- Competitive chess