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
command-line-interface10
http10
rspec10
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:48 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.
rmagickrubyimage-processingsketchupreplacement
shrinerb/shrine
Sep 2015 - Jan 2023
File Attachment toolkit for Ruby applications
Role in this project:Back-end Developer
Back-end DeveloperContributions:4 reviews, 2182 commits, 239 PRs in 7 years 5 months
Contributions summary:Janko primarily contributed to file attachment functionality within the Ruby-based "Shrine" repository. Their work focused on improving the handling of file uploads, including changes to the "Content-Disposition" header for S3 uploads and the implementation of features like client-side encryption support. The user also addressed issues related to file extension handling, database interactions (specifically, for PostgreSQL JSON columns), and the correct generation of URLs for uploaded files. They also contributed to adding test coverage and improving the overall stability of the file upload library.
file-attachmentfile-uploadattachmentdirect-uploadorigami
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