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About OKURA Masafumi

As a software developer

I'm a software developer based in Tokyo, Japan. My primary expertise is Ruby and Ruby on Rails.

I've been doing software development for over 10 years and been passionate.

I've been involved mostly in early stage projects, but also interested in improving/fixing legacy codes/apps.

I'm good at using tools such as RSpec and RuboCop with years of experiences.

I like Ruby so much that I've created several gems. Please visit GitHub if you're interested.

My primary focus of development is now on Alba, the fastest JSON serializer for Ruby. If you're looking for a way to serialize objects into JSON with Ruby, you can try it out.

I use Neovim as my primary text editor and I love it (in fact, I talked about my Neovim usage to over 100 people in tech conference devoted to Vim!)

If you'd like to know more about my development environment, please see my my dotfiles.

As a public speaker

I've given a few talks in medium-sized tech conferences such as VimConf 2018 and Nagoya RubyKaigi 04 (don't be confused with "real" RubyKaigi, this is local one).

I've given more than 10 tech talks in local meetups only in 2019. Topics vary from testing tips to introduction of communities to RuboCop training to live coding. Some of them were given in English.

As a community/conference organizer

I'm organizing a few Ruby communities in Tokyo and online: Grow.rb, Entaku.rb and Rubygems Code Reading Meetup.

I'm also a chief organizer of Kaigi on Rails, which started in 2020 as a new tech conference focusing on Web development.

I also was one of the organizers of VimConf 2019 which was successful.


I was born and raised in Japan and I'm a native speaker of Japanese. "OKURA" is my family name and "Masafumi" is my given name: we have family name first and given name last.

I practiced my English in Japan. My TOEIC score was 920 several years ago.

I enjoy brewing coffee. My Instagram account lists my photos on coffee.


On RubyConf 2021 I talked about Ruby method and how to control them.

I gave a talk about Vim usage with live coding (which didn't go successful) in VimConf 2018.

I gave a talk about having the smallest team with 2 developers and developing apps quickly and reliably (in Japanese).


I joined Roby Rogues a few times.


Hiring / General contact