Kosuke Yoshioka
Senior Full Stack Engineer at Pearly
California, United States
Summary
🤩
Rockstar🎓
Top SchoolKosuke Yoshioka is a Senior Full Stack Engineer based in California with a decade of software experience and 8+ years focused in fintech, known for leading ledger, payments, and billing rebuilds. He has driven end-to-end systems—from designing payment-account microservices and processor-agnostic payment architectures to implementing EU regulatory flows like 3DSecure—while managing small cross-functional teams and operational tooling. At Expensify he led the cashback program rollout for millions of users and built scalable batch systems for ACH reimbursements, blending product-facing work with deep backend domain knowledge. An active contributor to high-availability infrastructure, he has added cryptographic and job-management improvements to the Expensify Bedrock distributed database, showing comfort with systems-level engineering and testing. Practical, metrics-minded, and curious, he pairs a psychology/economics background with a full-stack bootcamp foundation to bridge product, compliance, and engineering effectively.
11 years of coding experience
9 years of employment as a software developer
Bachelor of Arts (B.A.) Psychology Economics Minor Marketing and Management Certificate, Bachelor of Arts (B.A.) Psychology Economics Minor Marketing and Management Certificate at Duke UniversityFull-Stack Web Developer, Full-Stack Web Developer at Dev BootcampThe Branson School
Github Skills (12)
c-language10
mbedtls10
cprogramming-language10
sha10
databases9
database9
database-design9
database-administration9
administration9
sqlite9
testing8
json6
Programming languages (5)
Github contributions (5)
Expensify/Bedrock
Mar 2018 - Jun 2022
Rock solid distributed database specializing in active/active automatic failover and WAN replication
Role in this project:
Back-end Developer & Database Engineer
Back-end Developer & Database EngineerContributions:3 releases, 1 review, 11 commits in 4 years 3 months
Contributions summary:Kosuke primarily contributed to the backend functionality of the Bedrock database system. Their work includes implementing cryptographic functions using SHA256 and HMACSHA256, enhancing data integrity and security. They also modified the Jobs plugin, introducing job ID management, and adding tests for job states and functionalities. In addition, the user has modified the test suite, demonstrating an understanding of system testing.
distributed-databasefailoverreplicationwan
ctkochan22/ctkochan22.github.io
Aug 2015 - Jun 2023
Personal Site of Chris Kosuke Tseng
Contributions:62 PRs, 81 pushes, 53 branches in 7 years 11 months
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