Mitsuhiro Shibuya
Software Engineer, Site Reliability at Mercari, Inc.
Tokyo, Japan
Summary
🤩
Rockstar🎓
Top SchoolMitsuhiro Shibuya is a Tokyo-based software engineer and engineering manager with 15 years of experience designing and operating high-scale server-side systems and site reliability practices. He blends hands-on backend development—especially in Ruby/Rails—and system architecture with people leadership, having led SRE and microservices transitions at Mercari and built high-throughput ad measurement platforms at Opt. An active open-source contributor, he has improved well-known projects like CarrierWave and flatpickr, tackling internationalization, security, and compatibility issues that improved stability for many users. Comfortable moving between full-stack fixes and organizational change, he focuses on pragmatic, product-oriented solutions that strengthen business outcomes. Notably, he has repeatedly launched SRE teams and introduced engineering practices that turned fragile systems into resilient production services.
15 years of coding experience
15 years of employment as a software developer
桐光学園高等学校
Japanese, English
Github Skills (25)
ruby-rails10
javascript10
jquery10
date-manipulation10
testing10
rails10
ruby10
localization10
dates10
file-upload10
html10
ruby-on-rails10
caching9
versioning8
activerecord8
Programming languages (8)
Github contributions (5)
carrierwaveuploader/carrierwave
Feb 2014 - Jan 2023
Classier solution for file uploads for Rails, Sinatra and other Ruby web frameworks
Role in this project:
Back-end Developer
Back-end DeveloperContributions:30 releases, 44 reviews, 317 commits in 9 years
Contributions summary:Mitsuhiro primarily worked on enhancing the file upload capabilities of the CarrierWave library, which is used for file uploads in Ruby web frameworks. Their contributions involved fixing issues related to file name extraction from URLs, making the cache storage pluggable, and improving features such as handling internationalized domain names. These changes culminated in several version releases that improved stability and functionality.
ruby-on-railsruby-gemsinatrarailsruby
JangoSteve/remotipart
Dec 2015 - Dec 2019
Rails jQuery file uploads via standard Rails "remote: true" forms.
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:44 commits, 29 PRs, 34 pushes in 4 years
Contributions summary:Mitsuhiro contributed significantly to the `remotipart` Rails plugin, focusing on features and compatibility improvements. They added support for Rails 5 and jQuery 3.x, fixed bugs, and implemented feature specifications. The user also addressed security concerns by mitigating potential XSS vulnerabilities and handling cases where parameters were unavailable. Furthermore, the user updated the version and made compatibility improvements with new features.
railsrubyjqueryfile-uploads
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