I'm Andi(@largo)! I like to automate things for myself and others, so I became a programmer! Please leave a comment or an issue if you try out any of my projects and cannot get it to work. I love meeting new people, say hello. お気軽にご連絡ください。
In January 2023 I wondered why require 'gtk3' took 3+ seconds on Windows. I traced it with Procmon and filed Bug #19378. The cause: Windows has no native realpath, so Ruby emulates it. Every require opened a handle on every parent directory of the file, and each open cost 8 syscalls. One file deep inside a gem (C:\Ruby32-x64\lib\ruby\gems\3.2.0\gems\glib2-4.0.8\lib\glib2\variant.rb) needed 80 syscalls, and the same work was repeated for every file.
In 2026 I tried GetFileInformationByName (Windows 11 24H2+), which gets the same information in one call, and attached a rough patch. Hiroshi Shibata did the careful part: he reworked it for ReFS, junctions and mount points, tested it thoroughly and merged it in ruby/ruby#18193. My original commit is part of it. In his benchmarks File.stat got about 3.9× faster and requiring big gems like rubocop or active_support 1.35–1.55× faster.
This should be in Ruby 4.1 this Christmas, so the short delay when a Ruby program starts on Windows gets noticeably shorter.
I also tried YJIT on Windows. It had never run there (#19325), and in August 2026 I got an experimental port working with a lot of help from AI. It mostly showed that it could be done. hsbt then wrote a proper implementation for mswin (ruby/ruby#19114), which passes the test suite and runs about 2× faster than the interpreter in his benchmarks. It is waiting for review now.
Thanks to nobu, hsbt and everyone who commented on these tickets over the years.
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Ruby in the browser (ruby.wasm)
- Largo/chunkybacon: Learn Ruby in the browser with Chunky Bacon. An interactive notebook course in German and English, running on ruby.wasm.
- Largo/jsg: the
jsgcommand creates, builds and serves ruby.wasm browser projects. Gem - Largo/nokogiri-pure: Nokogiri 1.19.4 in pure Ruby. libxml2, libxslt and gumbo ported to Ruby, no C extension, so it runs on ruby.wasm. Gem
- Largo/bigdecimal-pure: BigDecimal in pure Ruby.
require 'bigdecimal'still uses the native gem when it is available. Gem
Ruby + LLMs
- Largo/ruby_llm-claude_cli: use Claude Code and its subscription login as a RubyLLM provider. Streaming, images, PDFs, Office files, structured output and tool calls, no API key needed. Gem
- Largo/ruby_llm-providers-infomaniak: a RubyLLM provider for Infomaniak AI Tools (Swiss-hosted models). Gem
Office files
- Largo/ruby_pptx: a Ruby port of python-pptx. Create, read and update PowerPoint files. Gem
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Largo/ocran: Turn Ruby Scripts into .exe files. Now with Linux and MacOS Support. Cosmopolitain LibC Support means that a simple Rails app can be shipped as an executable and will run everywhere.
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Largo/HacketyHack: HacketyHack working in 2026. Includes clogs, which runs Shoes programs on plain CRuby with native widgets (libui), no browser engine or JVM needed.
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I got Ruboto: Ruby on Android to work with JRuby 10 largo/ruboto. This means Ruby apps working on Android phones and WearOS.
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Working on Drivers and PHP internals.
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My friend Yosei Ito made a tool prremote to run mruby on Rasberry pi pico and ESP32s, which runs on the cmd line. It works very well with AI, because of it. I made inkmodoro as a demo for it.
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Faster
requireon Windows, and YJIT on Windows, see above. -
Historical Swiss Weather: see high/low temperatures on a map
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Ruby.wasm Template This is a template to start using Ruby.wasm in the browser.
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Largo/ruby.wasm-quickstart: Your ruby scripts in the browser
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🔭 I’m currently working on improving Ruby for Windows. Checkout my ocra fork: ocran.
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👯 I’m looking to collaborate on Ruby! I went to Ruby Kaigi 2024, Ruby World 2024 and Ruby Kaigi 2026. Ruby now works anywhere: Windows, OSX, Linux, Android and the browser! Let's make it even easier for everyone to use it! I'm looking forward to Ruby Kaigi 2027 in Miyazaki, Japan, which I recommended to the organizers.
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🤔 Ruby on Windows can still get faster. Ideas are welcome!
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💬 Ask me about anything Ruby! See my Ruby Gems
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📫 How to reach me: see my email on my website!
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Talk to me in English, (Swiss-)German, Japanese or French!
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Favorite Editor: Micro and VSCode.
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DevOps: I've set up Devcontainers for VSCode so developers don't have to setup their own development environment. I self-host Gitlab.
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⚡ Fun fact: My approach to development is inspired by Derek Sivers. Check out this cool podcast
Fields of interest: Ruby, MRuby / Picoruby, PHP, Python, JavaScript/Typescript, C/C++/C#, SaaS, VSCode Devcontainers, Docker, Self-hosting, crossplattform (Linux, Windows, MacOS), ecommerce, single developer projects, talking to people and helping them using code, simple solutions like htmx
- How to compile ruby on Windows and debug with GDB
- How to programm in Ruby on rails your phone or android tablet
- Edit your website on your android phone using termux and git!
- Taking Website Screenshots with Ruby
- How to git diff epub, docx and sqlite files
- Ruby on the frontend demo app
- Exploring the Dynamic World of Animated SVG Favicons