Janus Troelsen
Software Contractor at Technische Universität Darmstadt
Copenhagen, Capital Region, Denmark
Summary
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Top SchoolJanus Troelsen is a seasoned software contractor based in Copenhagen with 14 years of hands-on experience across full-stack and backend systems. He brings deep open-source pedigree, contributing to high-profile projects like Electrum (Lightning Network support and Kivy UI optimizations) and Emscripten (web worker XHR improvements), as well as significant Haskell ecosystem work on Hackage, Servant, and Renovate. Janus excels at bridging low-level protocol and performance work with pragmatic developer tooling—implementing Simnet for Lightning testing, chunked worker XHRs, and Hackage integration for dependency automation. Comfortable in polyglot environments, he has repeatedly improved build processes, compatibility, and test coverage while fixing subtle cross-browser and compilation issues. Currently contracting through Progether, he pairs long-term open-source contributions with client delivery, making him a reliable engineer for complex integration and tooling challenges. An understated strength is his focus on developer experience: thoughtful APIs, robust testing, and maintainable build layouts that scale.
14 years of coding experience
Teknisk Erhvervsskole Center
English, Danish, German
Stackoverflow
20,768reputation
17.9mreached
322answers
83questions
mysql
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browser
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Github Skills (64)
dependency-management10
dependency-manager10
repeat10
javascript10
webworker10
package-management10
back-end-development10
dependency-analysis10
python10
lightning-network10
testing10
rust-wasm10
wasm-pack10
kivy10
hackage10
Programming languages (40)
Github contributions (5)
spesmilo/electrum
Mar 2018 - Dec 2019
Electrum Bitcoin Wallet
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:353 commits, 34 PRs, 453 pushes in 1 year 8 months
Contributions summary:Janus primarily worked on integrating features for Lightning Network support within the Electrum Bitcoin Wallet. Their contributions included adding and improving the user interface with Kivy, specifically incorporating the use of RecycleView for performance enhancements in lists and dialogs. Furthermore, the user implemented and tested Simnet support, which allows developers to simulate a Lightning Network. They also addressed bugs and optimized performance.
pythonelectrumlightningwalletcryptocurrency
haskell/hackage-server
Feb 2022 - Jan 2023
Hackage-Server: A Haskell Package Repository
Role in this project:Back-end Developer
Back-end DeveloperContributions:23 reviews, 23 commits, 32 PRs in 10 months
Contributions summary:Janus primarily focused on fixing compilation issues and enhancing the Hackage-Server. Their work involved modifications to core server features, including documentation generation, package indexing, and search functionalities. They also introduced improvements to the browse functionality by adding new endpoints and handling existing ones. Furthermore, the user updated the build process and layout, improving the overall structure of the server.
ghchackage-servercabalhaskellservant
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