Tetsuya Hasegawa
Member Of Technical Staff at xAI
Mountain View, California, United States
Summary
🤩
Rockstar🎓
Top SchoolTetsuya Hasegawa is a pragmatic senior software engineer and tech lead with nine years’ experience building high-throughput, highly available payment systems, most recently driving scalability and cost-efficiency at PayPay and now at xAI/X. He has led cross-functional teams across countries and owned critical platform components—from a central API gateway serving thousands of QPS to a vertical partitioning and archival solution that cut storage by 80%. His work on real-time rewards and parallelized message consumption delivered a 2.2x capacity boost and a 30% GMV uplift by integrating credit card flows into a large loyalty program. Based in Mountain View and holding interdisciplinary graduate training from the University of Tokyo, he combines systems-level architecture with hands-on implementation and a knack for operational simplicity under production pressure. An interesting non-obvious detail: he repeatedly moves between product-facing growth features and deep infrastructure work, showing comfort switching between customer impact and long-term platform engineering.
9 years of coding experience
6 years of employment as a software developer
University of TokyoKaisei Junior & Senior High School
Japanese, English, Korean
Github Skills (3)
javascript7
typescript6
markdown6
Programming languages (1)
Github contributions (4)
hasete2/hello-cms
Oct 2024 - Mar 2025
Contributions:5 pushes, 1 branch in 5 months
hasete2/crunch
Oct 2019 - Dec 2019
Contributions:3 pushes in 1 month
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