As an early member of the Paid Marketing and Attribution team(Growth), I designed and implemented an attribution system for affiliate marketing programs using Spark (Scala) and Django (Python). The system's robust initial design minimized the need for refactoring, even as multiple features were added.As a Staff Software Engineer, I led collaborations with various teams to develop new features for the attribution system, involving several system design and implementation iterations. Upon becoming the Tech Lead, I took a central role in planning and developing the project roadmap, providing technical insights that guided strategic decisions aligned with our objectives.Additionally, I integrated a reverse ETL tool(Hightouch) for activation, which required extensive work with data infrastructure, particularly Databricks. I also manage signals to third-party marketing platforms via Google Tag Manager, utilizing both web and server-side containers.Throughout multiple projects, I have mentored other engineers through one-on-one sessions and code reviews, ensuring high-quality deliverables and fostering a collaborative team environment.

I worked on the device advertising platform team at Amazon, engaging in system design and implementation using React for the frontend and Java for the backend. Key projects included:- Developing an interactive ad creation tool for Fire Tablet by transitioning some frontend modules to micro services, building an asset management backend service for cloud asset upload and serving, and refactoring a heavy React frontend app.- Designing and implementing the ad serving and tracking system for the Out of Box Experience (OOBE) on Fire TV, adhering to IAB standards and addressing resource contention challenges on low-power devices. The OOBE is the initial page where users select their first apps upon first turning on the Fire TV.- Designing APIs and implementing the frontend for a self-serve Fire TV ad management platform, including building a service for ad management and developing a React app.Throughout these projects, I collaborated with multiple teams to design and implement new features while navigating Amazon's complex in-house tech ecosystem.

ADVR is an early-stage startup that developed an ad platform for VR (Virtual Reality) apps. My responsibilities included building a 3D asset management system, ad campaign management, serving, targeting, and event tracking for ads. The tech stack consisted of AWS Lambda, AWS Kinesis, MySQL, Redis, Python, Flatbuffers, Pyramid, React, Redux, Three.js, and Unity3D. As a software engineer in a very small team, I had the opportunity to work across the entire tech stack.

Goodshop is an affiliate marketing publisher that supports non-profits. Goodshop managed multiple webpages with coupon information, sharing profits from purchases with users' chosen non-profit organizations. As a full-stack engineer working with a Ruby on Rails app, I handled integration with email marketing platforms like Cordial, optimized SQL queries to improve website performance, built a location-based app, and designed and refactored the revenue reporting system for non-profits.

Kakao, the most popular mobile messenger in South Korea. At that time, Kakao was a fast-growing startup, now a major tech company with a $14.2 billion market cap. My team focused on e-commerce within the messenger app. I was responsible for refactoring the entire frontend app from jQuery to a single-page Angular app, building APIs and backend systems to handle high volumes of traffic (before cloud services like AWS were available in Korea), and developing monitoring and log collection systems.The tech stack included Elastic Search, Redis, Memcached, MySQL, Java, Rails, Ruby, Play Framework, AngularJS, Grunt, Logstash, and Kibana.

Tech Stack: Ruby, Rails, MySQL- Built REST API end-points for Android/iPhone app- Designed entire database schema- Implemented a location-based search engine, crawler, notification, CMS