Seattle, WA·Currently at Meta, on Facebook Marketplace

Charlie Liu.Senior software engineer
who builds consumer products.

Right now I work on AI features and A/B tests for Facebook Marketplace. Before that I ran the feature-flag service at Dropbox, and before that I wrote software for medical devices.

Years shipping
0+
Experiments shipped
0+
Annualized rev. impact
$0M+
Daily active users impacted
150M+

Where I've worked.

Most recent first. Product engineering, platform work, and experimentation infrastructure.
2023 — Now

Senior Software Engineer · Meta — Facebook Marketplace

Led the first generative AI features on Marketplace listing pages (Product Insights and Vehicle Insights), which reached 39.4% adoption and 51.9% 14-day retention. Ran 200+ experiments that together added 300K+ daily sessions and about $7M in annualized revenue. Also launched Screenshot to Share, which grew to about 1.5M uses a day.

typescriptreact / relayhack / phpgraphqla/b testingllm pipelines
Revenue impact
$7M+
annualized, 200+ exps
2021 — 2023

Software Engineer · Dropbox — Experimentation Platform

Owned the feature-flag and rollout service, which handled 40M requests per second across a large part of Dropbox. Led the move from REST to gRPC. Built a system to expire old experiments, which cut high-severity incidents in half, and a new experiment setup flow that made setup 30% faster.

gopythongrpcfeature flagsexperimentation
P2+ incident rate
−50%
via expiration system
2019 — 2021

Software Engineer · Promenade — Platform & Devices

Built full-stack and embedded software for connected devices, including Class II medical devices. Owned the deployment pipeline and the backend for over-the-air updates and device data, using AWS, Django, S3, DynamoDB, Docker, and Yocto.

python / djangoawsdockerembedded / yoctoota updates
Device class
FDA II
medical & IoT

↳ More detail in my résumé, or just ask.

How I work.

A bit more than what fits on a résumé.

I've been a software engineer for about six years, at Meta, Dropbox, and Promenade. At Meta I led the first generative AI features on Marketplace listings. At Dropbox I owned the feature-flag service, which handled around 40 million requests per second. Promenade was a small company, so I did a bit of everything there, including embedded work on medical devices.

Most of my work has involved A/B testing in some way. I like to plan the experiment and the rollout while I'm still writing the code, so everyone agrees on what we're measuring before launch. My favorite projects have usually needed a lot of back-and-forth with PMs, designers, data scientists, and sometimes legal, and I'm comfortable being the engineer who keeps that moving.

I also care about the less visible parts of the job: good tests, keeping latency down, and on-call docs that someone else can actually follow.

Strengths
Consumer product work, A/B testing, AI features, backend platforms, reliability, working across teams.
Languages
TypeScript, JavaScript, Python, Go, Hack/PHP, C++
Frontend
React, React Native, Relay, GraphQL, Redux, Swift
Backend
gRPC, REST, feature flags, experimentation systems, AWS, Docker, CI/CD, Django
Currently
Local-first apps, and better ways to test LLM agents.

Side projects.

Apps I made for myself, plus an open-source tool I contribute to.