Mark Siemers
Sabbatical
Cincinnati, Ohio, United States
Summary
🤩
Rockstar🎓
Top SchoolMark Siemers is a seasoned software engineer and leader with 11 years of experience building scalable web applications and leading teams to measurable business outcomes. He has a strong track record of improving people, processes, software, revenue, and profit—driving initiatives that saved $2M/year in infrastructure and enabled systems processing billions of records. As Director of Engineering and former manager/lead across startups and enterprises, he combines hands-on backend work (notably contributions to the Amber Crystal web framework) with pragmatic architectural and hiring improvements. He led a rapid test-suite overhaul that raised coverage from 13% to 95%, enabling a zero-downtime Rails upgrade, and built data-import and rules engines that directly doubled revenue and supported massive daily throughput. Based in Cincinnati, he pairs business training from Kelley School of Business with deep technical fluency across Ruby/Rails, Crystal, databases, and cloud infrastructure. On sabbatical now, he remains an active open-source contributor focused on developer experience and reliable tooling.
11 years of coding experience
16 years of employment as a software developer
MS, Business and Information Systems, MS, Business and Information Systems at Indiana University - Kelley School of Business
English
Stackoverflow
631reputation
82kreached
21answers
5questions
Github Skills (17)
crystal-lang10
code-generation10
cli10
websocket9
rspec9
docker8
cicd8
dockers8
activerecord6
coldfusion6
ruby-on-rails6
sql-server6
metaprogramming6
sql6
pg6
Programming languages (9)
Github contributions (5)
amberframework/amber
Oct 2017 - Mar 2018
A Crystal web framework that makes building applications fast, simple, and enjoyable. Get started with quick prototyping, less bugs, and blazing fast performance.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:11 commits, 27 PRs, 39 pushes in 4 months
Contributions summary:Mark primarily focused on enhancing the Amber web framework's core functionality and improving the developer experience. They implemented and refined generator features, especially for multi-word names, and ensured consistent naming conventions across various code generation processes like scaffolding, models, controllers, and migrations. Furthermore, they addressed database naming conventions for PostgreSQL, MySQL, and SQLite, including updates to the database configuration and Docker Compose setup, indicating a strong emphasis on infrastructure and database integration. Finally, the user added 'help' options to CLI commands and also implemented features for websocket routes.
web-frameworkcrystalcohesiveframeworkamber
marksiemers/ruby-to-crystal
Nov 2017 - Jul 2020
Contributions:29 commits, 4 PRs, 24 pushes in 2 years 8 months
benchmarksrubycrystal
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