Eitaro Fukamachi
Software Engineer at synchronit
Tokyo, Japan
Summary
🤩
Rockstar🎓
Top SchoolEitaro Fukamachi is a software engineer with 16 years of experience designing and shipping high-concurrency backend systems, payments platforms, and hardware-integrated services. He specializes in backend architecture and long-term maintainability, with uncommon deep expertise in Common Lisp alongside modern web stacks. Eitaro has led production deployments that improved performance under heavy load—migrating ad-network backends to Common Lisp for a 1.6x throughput gain and architecting coin-handling/payment systems used in the field. A prolific open-source maintainer, he authored and improved key Lisp projects (including the widely used roswell launcher and the lem editor) and contributed performance optimizations to non-blocking HTTP servers. Currently remote in Tokyo, he works on autonomous system software and internal tooling for US-based startups while also developing a DSL-driven PaaS. His blend of low-level tuning, high-concurrency design, and long-term library maintenance makes him a rare engineer who bridges production reliability and language-level craftsmanship.
17 years of coding experience
10 years of employment as a software developer
Information Science, Dropped out in 3rd grade., Information Science, Dropped out in 3rd grade. at Tokyo University of Science
English, Japanese
Github Skills (24)
editors10
text-editor10
scripting10
editor10
cicd10
refactor10
binding10
script10
common-lisp10
performance-optimization10
parse10
command-line10
webserver10
sh10
functional-programming10
Programming languages (17)
Github contributions (5)
fukamachi/clack
Jan 2011 - Dec 2022
Web server abstraction layer for Common Lisp
Role in this project:
Back-end Developer
Back-end DeveloperContributions:2 reviews, 1119 commits, 60 PRs in 12 years 1 month
Contributions summary:Eitaro added multiple modules to the project, demonstrating a focus on building out a web server abstraction layer in Common Lisp. The commits involve the creation of an "application" module, the addition of a "server" module, and the implementation of core functionality including a request dispatcher. Furthermore, the user defined key classes and methods for the project's underlying structure.
common-lispwebserver
fukamachi/woo
Oct 2014 - Jun 2022
A fast non-blocking HTTP server on top of libev
Role in this project:Back-end Developer
Back-end DeveloperContributions:1 review, 388 commits, 63 PRs in 7 years 9 months
Contributions summary:Eitaro significantly improved the performance of the HTTP server, woo, by optimizing the HTTP parsing process. They achieved this by leveraging lower-level APIs of the `fast-http` library. Subsequent commits further enhanced efficiency by removing dependencies on `puri` and `do-urlencode` and by optimizing URL parsing and decoding, ultimately leading to a faster and more efficient web server. They also refactored the project into multiple packages for better code organization.
http-serverlibevnon-blockingcommon-lispwebserver
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