4x founder

Alexandra Kissel

Software Engineer | Ex YC-Founder

Founder

Rubber Ducky Labs· Winter 2023 🇺🇸 San Francisco, California, United States

in LinkedIn 𝕏 @alexandraj777

2025Software Engineer· Sierra

Founder · since 2015

Company

Sierra

Role

Software Engineer

Stage

—

no public source

Raised

—

no public source

Based

San Francisco, California, United States

Founder / co-founder — the company's markEmployee / research role

Source: LinkedIn work history

Profile coverage5 of 7 · missing posts, contact

Rubber Ducky Labs

AI Powered Product Discovery

Winter 2023

Experience

Career

Sierra
Software Engineer · San Francisco, California, United States · 2025
2025
Rubber Ducky Labs
Founder
Founder and CEO · San Francisco, California, United States · 2022 – 2025
2022
South Park Commons
Founder
Member · San Francisco, California, United States · 2022
2022
Gantry
Founder
Founding Product Manager · San Francisco, California, United States · 2021
2021
Citrine Informatics
AI Product Manager · Redwood City, CA · 2020 – 2021
2020
SigOpt
Platform Lead · San Francisco Bay Area · 2017 – 2019
2017
SigOpt
Founder
Founding Software Engineer · San Francisco Bay Area · 2015 – 2017
2015
Polyvore
Software Engineer · Mountain View, CA · 2014 – 2015
2014
Rent The Runway
Software Engineering Intern · Greater New York City Area · 2013
2013
Facebook
Software Engineering Intern · Menlo Park, CA · 2012
2012
Duolingo
Software Engineering Intern · Greater Pittsburgh Area · 2011
2011

Bio

Alexandra (née Johnson) has spent eight years in the ML tooling industry (starting with a 4-year stint as the first software engineer at @SigOpt) to help make the state of the art in machine learning effortless and easy to use. Before that, she worked on recommender systems in fashion tech. She founded Rubber Ducky Labs to be the suite of dream tools that she wished she had while working on recommender systems.