Sjon Hortensius
Brandweervrijwilliger at Parse Software Development B.V.
Randstad, Netherlands
Summary
🤩
Rockstar🎓
Top SchoolSjon Hortensius is a seasoned web applications developer with 14 years of experience building high-performance systems using PHP, Go, MySQL and PostgreSQL, currently focused on sub-millisecond APIs and system reliability. He manages production at scale as a Linux System Administrator at Postcode.eu, keeping globally replicating environments near 100% uptime while serving millions of daily hits. His open-source contributions include significant UI and UX work for the well-known pfSense project—migrating interfaces to Bootstrap and adding drag-and-drop widgets—and backend performance and stability improvements for Cacti. Specializing in performance tuning and security, he combines deep backend expertise with practical front-end improvements and a history of evolving legacy codebases into maintainable, efficient systems. Based in the Randstad, he also volunteers as a firefighter, reflecting practical teamwork and calm under pressure.
13 years of coding experience
14 years of employment as a software developer
Hoger algemeen voortgezet onderwijs, Hoger algemeen voortgezet onderwijs at Groene hart lyceumBachelor, Information Technology, Bachelor, Information Technology at De Haagse Hogeschool / The Hague University of Applied Sciences
English, Dutch
Github Skills (17)
bootstrap10
css10
ui-design10
uid10
php10
front-end-development10
html10
pfsense10
bootstra10
web-development10
cacti10
javascript9
graph9
graphing9
firewall8
Programming languages (18)
Github contributions (5)
pfsense/pfsense
Dec 2014 - Jan 2016
Main repository for pfSense
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:312 commits, 3 PRs, 5 comments in 1 year
Contributions summary:Sjon was involved in a significant project to migrate the pfSense interface to the Bootstrap framework. They focused on converting core parts of the interface, including the index page and various widgets. Their contributions also touched upon the user interface styling, CSS modifications, and restructuring of the file structure to better align with the new Bootstrap-based design. Additionally, they implemented new features like tabs and the drag-and-drop functionality for widgets, showcasing a strong understanding of front-end design and user interface enhancement.
netmikofirewall-rulesrouterospfsensefreebsd
Cacti/cacti
Jan 2016 - Jan 2016
Cacti ™
Role in this project:Back-end Developer
Back-end DeveloperContributions:7 commits, 2 PRs, 5 comments in 4 days
Contributions summary:Sjon contributed to bug fixes, performance improvements, and code refactoring within the Cacti project. They addressed issues related to upgrades, corrected typos in settings, and enhanced code efficiency by replacing deprecated functions and employing `microtime(true)`. Additionally, the user implemented support for RRDTool 1.5 and refactored code to improve stability. The user primarily focused on improving the back-end functionality and maintainability of the project.
graph-templatingrrdtoolcacti-frameworkcactiphp
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.