Jack Kinsella
Founder at Semicolon Berlin
Berlin, Germany
Summary
👤
Senior🎓
Top SchoolJack Kinsella is a founder and freelance software engineer based in Berlin with 14 years of professional experience building and leading product-focused engineering teams. He has launched and scaled businesses—from a Ruby on Rails marketplace that reached 3 million users annually and was successfully sold, to political apps for major European parties—and steps in as a strong technical lead during transitions such as post-acquisition handovers. Technically pragmatic, Jack emphasizes durable architectures, testing discipline (hundreds of CI tests), reusable components, and clear onboarding—authoring 200 pages of training material for junior engineers. His work spans web, AI, and AR projects for clients like TÜV Nord and academic research for the University of Potsdam, plus practical open-source contributions fixing routes, controllers and helpers in Rails social auth tooling. He combines product-level business judgment (multi-territory operations and exits) with hands-on backend engineering, favoring long-lived technologies over faddish choices. An Oxford-educated jurist turned engineer, he brings a rare blend of legal, commercial and technical fluency to complex, real-world software problems.
14 years of coding experience
14 years of employment as a software developer
BA Jurisprudence, BA Jurisprudence at University of OxfordHacker RetreatData Science, Data Science at Data Science RetreatSt. Joseph's College, Galway
English, German, Spanish
Github Skills (12)
spreed10
ruby-rails10
devise10
spree10
rails10
omniauth10
ruby10
configuration-management9
rest-api8
api-rest8
restful-api8
api-design8
Programming languages (12)
Github contributions (5)
spree-contrib/spree_social
Feb 2013 - Mar 2014
Building block for spree social networking features (provides authentication and account linkage)
Role in this project:
Back-end Developer
Back-end DeveloperContributions:12 commits in 1 year 1 month
Contributions summary:Jack primarily contributed to bug fixes and code enhancements within the `spree_social` repository. They addressed issues related to missing helper functions, incorrect route namespaces, and controller errors. These changes involved modifying controllers, routes, and configuration files. The contributions improved the functionality and stability of the social networking features provided by the project.
social-networklinkagerails-engineaccountauthentication
jackkinsella/confessions
Mar 2016 - Jan 2018
Contributions:3 PRs, 146 pushes, 2 branches in 1 year 10 months
confessions
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