Holger Sindbæk
Founder at Online Solitaire
New York, New York, United States
Summary
👤
Senior🎓
Top SchoolHolger Sindbæk is a designer-turned-developer and founder with 13 years of experience building consumer web and mobile products, currently based in New York. He blends strong UI/UX instincts with hands-on engineering in Ruby on Rails, React/React Native and iOS (Objective-C/RubyMotion), having shipped high-traffic platforms like Online Solitaire and World of Card Games. As CTO and co-founder of Slang he built the iOS app, web platform and transaction API that supported 250k users and integrations with Stripe, PayPal and complex fulfillment flows. Holger is also an active open-source contributor to iOS tooling (e.g., BubbleWrap and DFImageManager), demonstrating attention to cross-version compatibility and polished front-end behaviors like image animations. He runs his freelance studio BetaUnltd, balancing client work with side projects that drive significant daily engagement (Online Solitaire sees millions of monthly games). His rare combination of product design sensibility and full-stack execution makes him comfortable taking an idea from mockup to production at scale.
13 years of coding experience
9 years of employment as a software developer
Higher Vocational Degree Multimedia Design and Communication, Higher Vocational Degree Multimedia Design and Communication at KEA - Københavns ErhvervsakademiHigher Vocational Mobile Application Development, Higher Vocational Mobile Application Development at Hyper IslandStudy course Computer Programming, Study course Computer Programming at Recurse Center
Stackoverflow
2,324reputation
329kreached
31answers
101questions
Github Skills (17)
rubymotion10
ios10
animation10
rspec10
image-loading10
swift10
imagemagick6
ruby-on-rails6
xcode6
amazon-ec26
iphone6
mongoid6
ui-design6
ux-design6
objective-c6
Programming languages (16)
Github contributions (5)
rubymotion-community/BubbleWrap
Jul 2013 - Oct 2015
Cocoa wrappers and helpers for RubyMotion (Ruby for iOS and OS X) - Making Cocoa APIs more Ruby like, one API at a time. Fork away and send your pull requests
Role in this project:
Mobile Developer (iOS)
Mobile Developer (iOS)Contributions:6 commits, 4 PRs, 2 comments in 2 years 4 months
Contributions summary:Holger contributed to the `bubblewrap` repository, focusing on iOS-specific features. Their primary contributions involved adding the `interface_orientation` method to the `device.screen` module and creating corresponding tests. The user also addressed a bug in the `simulator?` method, ensuring correct behavior across different iOS versions and environments, essential for RubyMotion development. The work demonstrates expertise in RubyMotion and iOS development.
apirubymotionrubypull-requestsswift
kean/DFImageManager
Mar 2016 - Mar 2016
Image loading, processing, caching and preheating
Role in this project:Mobile Developer (iOS)
Mobile Developer (iOS)Contributions:6 commits, 1 PR in 1 day
Contributions summary:Holger's contributions focused on enhancing the `DFImageView` class within the iOS image loading library. They added the ability to set the animation duration for image fade-in effects. The changes involved modifying both the header and implementation files, including updating properties and animation logic. This modification aims to provide developers with more control over the visual presentation of images within the application.
imageuiimagecachingsdwebimageimage-processing
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