Joonsung Lee
VP Of Engineering at Devsisters
Seoul, South Korea
Summary
🤩
Rockstar🎓
Top SchoolJoonsung Lee is a seasoned backend engineer and engineering leader with 15 years of experience, currently serving as VP of Engineering at Devsisters in Seoul. He has risen through hands-on roles from developer to Sr. DevOps Manager, combining deep operational expertise with product-facing backend systems for mobile games. His open-source contributions include implementing QUIC protocol support and integrating BoringSSL for high-performance UDP transport, reflecting strong network, crypto, and systems programming skills not always visible in game studios. A KAIST computer science graduate, he balances low-level protocol work with large-scale service delivery and team leadership. Colleagues rely on him for pragmatic engineering decisions that bridge performance-critical servers and robust DevOps practices.
15 years of coding experience
Bachelor of Science (BS), 컴퓨터 과학, Bachelor of Science (BS), 컴퓨터 과학 at 한국과학기술원(KAIST)
English
Github Skills (7)
boringssl10
c-language10
go10
cprogramming-language10
quic10
cryptography10
network-programming10
Programming languages (9)
Github contributions (5)
devsisters/goquic
Jan 2015 - Jun 2017
QUIC support for Go
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1 release, 184 commits, 4 PRs in 2 years 5 months
Contributions summary:Joonsung contributed to the development of QUIC protocol support for Go, primarily focusing on the server-side implementation. Their work involved creating core components like the GoQuicServerPacketWriter and implementing essential functionalities for handling and processing packets. The commits showcase the initiation of the QUIC protocol's data handling mechanism and the addition of key structures for managing connections. The user demonstrated knowledge of network programming and the QUIC protocol specification through their code changes.
golangquichttp3tls13ietf
devsisters/libquic
Jan 2015 - Sep 2016
QUIC, a multiplexed stream transport over UDP
Role in this project:Back-end Developer
Back-end DeveloperContributions:4 releases, 62 commits, 7 PRs in 1 year 8 months
Contributions summary:Joonsung added support for the BoringSSL library and made related changes to include the necessary crypto libraries. The user also introduced a Chromium source and made additions to `getdep.py` to add debugging capabilities. Furthermore, the user made more changes, including the addition of quic_crypto_server_stream and supporting dependencies, the implementation of curve25519-donna.c and other encryption and decryption files.
non-blockingquicprotocolwebtransportstream
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