Aaron
Coplan

I’m a staff engineer at Meta building the systems that let our apps work together — currently shipping cross-app experiences between WhatsApp, Facebook, and Instagram.

Aaron Coplan

Product engineer, with platform depth.

Currently working on Cross App Experiences at Meta, using AI to deliver seamless product experiences to 3 billion users. I’m passionate about building user-facing products but never afraid to dive into the infrastructure underneath them. In my free time I love tennis, travel, and reading.

Experience.

2025—present

Staff Software Engineer · Cross App Experiences · Meta

Led a 10-engineer effort across two orgs to ship Meta’s account switcher in WhatsApp, adding 1M+ monthly users. Architected the Android platform behind WhatsApp’s cross-app experiences while upholding strict privacy requirements — foundational infrastructure that powers opt-in features like account linking and crossposting.

2023—2025

Staff Software Engineer · Facebook Design Systems · Meta

Led engineering on Facebook’s 2023 brand refresh — new Reactions, a ground-up icon redesign, and a fresh color palette — which became the template for every Meta visual refresh since. Built the design-token platform beneath it (the source of truth for visual design across 5 design systems and 6 UI frameworks) and shipped the Newsfeed redesign that drove $300M+ in annual incremental revenue.

2019—2023

Software Engineer → Senior Software Engineer · Facebook Product Quality · Meta

Built and owned UI Quality Review, Meta’s automated tool for catching accessibility and usability bugs across iOS, Android, and Web. Embedded it into the company’s code-review process, scaling adoption ~10× year-over-year to 1,400+ code changes and 2,000+ design screens reviewed.

Personal projects.

PROJECT · 01

shuffler

A better shuffle for Spotify — genuinely random, multi-source, and tunable. Native iOS, playing through Spotify’s SDK.

Swift · SwiftUI · Spotify SDK
TestFlight
PROJECT · 02

what2wear

An AI personal stylist. Suggests outfits from your real wardrobe based on weather, calendar, and recent wear — reasoning runs on Claude.

React Native · Spring Boot · Claude
TestFlight
PROJECT · 03

paaron

A Claude-powered personal assistant. Reads my email, calendar, and to-dos, thinks overnight, and sends a synthesized morning briefing.

Python · Claude · sqlite-vec · GCP
Private
PROJECT · 04

waterfall

A brand-new compiled programming language with powerful static analysis, transpiling to multiple targets: JavaScript, Python, and C99.

Kotlin
GitHub
MORE ON GITHUB

Skills

Languages
Swift · Kotlin · TypeScript · JavaScript · Java · Python · SQL · Hack/PHP
Frameworks & Platforms
React · React Native · Spring Boot · GraphQL · PostgreSQL · AWS · GCP
AI
Claude Code · Anthropic SDK

Say hello.

Don’t hesitate to reach out for any reason — my inbox is always open!

Email me