Janko Marohnić
Senior Ruby Engineer at ButterflyMX®
Brno, South Moravia, Czechia
Summary
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RockstarJanko Marohnić is a Senior Ruby Engineer with 14 years of experience, currently building backend systems at ButterflyMX from Brno, Czechia. He is a prolific open-source maintainer and contributor—author of the Shrine file-attachment toolkit and contributor to prominent projects like Rack, Rails, AWS SDK for Ruby, Roda, and Falcon—bringing deep expertise in web servers, authentication, storage, and performance. His work often focuses on robustness and efficiency: from reducing memory allocations in Falcon and optimizing Rack input handling to improving S3 uploads and multipart parsing. He combines hands-on bug fixes and feature additions with test-driven improvements across the Ruby ecosystem, including image processing and HTTP client tooling. Notably, he has shaped authentication flows in Rodauth and driven practical enhancements to ActiveStorage and Shrine that affect real-world file upload workflows. Pragmatic and detail-oriented, he thrives on refining libraries that power scalable, reliable web applications.
14 years of coding experience
5 years of employment as a software developer
Stackoverflow
9,125reputation
1.5mreached
68answers
49questions
amazon-s3
top-5%
ruby-on-rails
top-5%
Github Skills (95)
clientside10
image-processing10
vimscript10
plugin-development10
testing10
rspec10
command-line-interface10
http10
authentication10
test-framework10
webpages10
web-content10
vim10
ruby10
http-client10
Programming languages (20)
Github contributions (5)
minimagick/minimagick
Sep 2014 - Dec 2022
mini replacement for RMagick
Role in this project:
Back-end Developer
Back-end DeveloperContributions:49 releases, 2 reviews, 262 commits in 8 years 4 months
Contributions summary:Janko contributed to the mini_magick project by implementing new features and making enhancements to existing functionalities. They added support for accessing dimension attributes using strings, introduced a debug mode and timeout settings, and encapsulated Windows-specific functionalities within dedicated utilities. Furthermore, the user simplified the processor selection mechanism and made code improvements, which resulted in enhanced stability and robustness for the library.
rmagick
vim-test/vim-test
Dec 2014 - Jan 2023
Run your tests at the speed of thought
Role in this project:QA Engineer / Test Automation Engineer
QA Engineer / Test Automation EngineerContributions:1 review, 268 commits, 169 PRs in 8 years 2 months
Contributions summary:Janko primarily focused on writing and maintaining tests for the `vim-test/vim-test` repository, which aims to provide a test runner for the Vim editor. They added tests for new testing frameworks like GoTest, Busted, and for features such as passing options. Their work involved modifying test files, adding new testing frameworks to the plugin, and ensuring existing tests functioned correctly. The user's commits involved setting up tests for different testing frameworks and granularities, improving the test command strategy, and ensuring the tests are runnable.
speedvimtestingthoughttest-runner
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