Seongju Lee

I'm a software engineer building systems across healthcare, real estate, and consumer analytics. Currently at Berry Street. Previously at Thirty Madison (acquired), where I helped scale the platform from Series B to $250M ARR serving 2M+ patients.

I enjoy architecting backend systems, leading cross-functional teams, and delivering measurable business impact.

You can find me on github and LinkedIn, or send me an email.

Skills

Languages: JavaScript (ES6+), TypeScript, Ruby, SQL

Front-End: React, React Native, Next.js

Back-End: Node.js, NestJS, Ruby on Rails

Data: PostgreSQL, Elasticsearch, Redis, Kafka, RabbitMQ, Snowflake, Spark, Hadoop

Cloud & DevOps: AWS, Kubernetes, Docker

Experience

Berry Street Dec 2024 – Present

Senior Software Engineer

Thirty Madison Aug 2021 – Dec 2024

Senior Software Engineer → Staff Software Engineer

Led backend development for telehealth platform serving 2M+ patients. Architected workflow orchestration service and treatment payment system handling 9M+ transactions. Migrated core services from Rails monolith to service-oriented architecture.

Remine Oct 2017 – Aug 2021

Full Stack Engineer → Engineering Manager → Technical Lead

Led team responsible for nationwide real estate listing search platform serving 50K+ agents. Managed two development teams building prospecting tools and integrations.

Comscore May 2015 – Oct 2017

Software Engineer

Worked on analytics platform for cross-media viewership, processing hundreds of terabytes of consumer data daily. Developed data pipelines using Spark and Hadoop.