Junseok Lee
Back End Developer at TikTok
Seoul, Singapore
Summary
👤
Senior🎓
Top SchoolJunseok Lee is a seasoned backend developer with 11 years of experience building and operating high-throughput, scalable services for B2B SaaS and consumer platforms. He has driven backend architecture and feature delivery at scale—supporting tens of millions of MAU at ZEPETO and handling 70M monthly requests and multi-million message campaigns at Channel.io—using Java, DynamoDB, Kafka/Kinesis patterns, and AWS tooling. Comfortable leading small engineering teams, he has shipped production systems from delayed-queue pipelines to DKIM email integrations and bulk-processing APIs while also doing hands-on migrations of hundreds of millions of items with minimal downtime. Now at TikTok’s Platform team, he focuses on server architecture and platform reliability, valuing candid cross-functional communication and rapid user-feedback cycles. Outside work he documents engineering experiments and learnings on his blog and GitHub, reflecting a practical interest in reproducible, production-ready engineering rather than academic proofs.
11 years of coding experience
5 years of employment as a software developer
Faculty of Electronics and Information Technology, Faculty of Electronics and Information Technology at Warsaw University of TechnologyBachelor's degree School of Computing, Bachelor's degree School of Computing at Korea Advanced Institute of Science and Technology
English, Korean
Github Skills (70)
python10
deep-learning10
neural-network10
data-science10
tensorflow10
machine-learning10
ml9
deep-neural-networks9
cli8
linux8
othello8
command-line8
pytorch8
lifecycle8
nexus8
Programming languages (12)
Github contributions (5)
2JS/DBB
Jan 2015 - Aug 2020
Contributions:6 PRs, 6 pushes, 8 branches in 5 years 7 months
2JS/Actions
Dec 2019 - May 2024
Repository to Test & Study GitHub Actions
Contributions:2 PRs, 7 pushes, 3 branches in 4 years 5 months
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