Jason Karns
Double Agent at Test Double
Columbus, Ohio, United States
Summary
🤩
Rockstar🎓
Top SchoolJason Karns is a seasoned web developer and longtime contributor in the Ruby and JavaScript ecosystems, bringing 16 years of experience building standards-driven, accessible web applications from server to front end. Known at Test Double as a “Double Agent,” he blends backend Rails and Sinatra expertise with Node and rich-client frameworks like Backbone and Ember to deliver maintainable, well-tested systems. He has a strong testing and tooling focus—improving test runners, CI, and package formulas for high-impact OSS projects including Homebrew and Rails’ Active Support. Jason’s background spans enterprise and startup work (GitHub, Shutterstock, New Relic) and includes legacy-to-modern migrations and performance tuning, reflecting a pragmatic approach to technical debt. Based in Columbus, Ohio with a CS degree from Ohio State, he pairs deep hands-on skills (git, vim, REST, microformats, accessibility) with a knack for improving developer workflows and testability. An uncommonly practical open-source maintainer, he’s fixed build systems, test reporters, and package installs that many teams silently rely on.
16 years of coding experience
18 years of employment as a software developer
Graham High SchoolBS, Computer Science & Engineering, BS, Computer Science & Engineering at The Ohio State University
English, German
Stackoverflow
1,802reputation
119kreached
13answers
3questions
npm
top-5%
Github Skills (55)
application-framework10
ruby-rails10
javascript10
coffeescript10
web-application10
package-management10
testing10
app-framework10
rspec10
authentication10
user-authentication10
bash10
rails10
test-reporting10
travis-ci10
Programming languages (30)
Github contributions (5)
nodenv/nodenv
Jun 2015 - May 2022
Manage your app's Node.js environment
Role in this project:
DevOps Engineer
DevOps EngineerContributions:7 releases, 239 commits, 173 PRs in 7 years 1 month
Contributions summary:Jason's contributions primarily revolve around enhancing the testing infrastructure and improving the build process of the nodenv project. Their work includes setting up and configuring testing environments using tools like Bash and Bats, and optimizing the Continuous Integration process on Travis CI. The user also focused on streamlining the build process through the introduction of a configure script, and improving the overall stability and efficiency of the testing framework. This involved code changes to testing helper files and completion scripts.
nodejsnodenvnodeversion-managershell
linemanjs/lineman
Apr 2013 - Jun 2017
Lineman helps you build fat-client JavaScript apps. It produces happiness by building assets, mocking servers, running specs on every file change
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:1 release, 75 commits, 10 pushes in 4 years 2 months
Contributions summary:Jason contributed to the LinemanJS project by improving the build process and test suite. They fixed banner issues for JavaScript concatenation and implemented the images and webfonts tasks using Grunt's copy functionality. Furthermore, the user refactored the task loading mechanism and updated dependencies, enhancing the overall maintainability and efficiency of the project.
javascriptmocking
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