Kristián Feldsam
Founder & CTO at FeldHost™
Prague, Prague, Czechia
Summary
🤩
Rockstar🎓
Top SchoolKristián Feldsam is a founder and CTO based in Prague with 14 years of engineering experience and over six years running his own hosting and cloud business, FeldHost™, focused on product development and infrastructure architecture. He blends hands-on full-stack web development with DevOps expertise, having implemented and customized OpenNebula for open-source cloud deployments and contributed bug fixes and feature enhancements to its core. Kristián has a strong background in front-end technologies and responsive design from large media and e‑commerce projects, while also improving backend and Dockerized deployments in notable open-source projects like mailcow. He’s comfortable moving between client-facing product work and low-level operational fixes—optimizing API calls, VM log handling, and UI glitches—so projects ship reliably. Known for pragmatic rewrites and clean coding standards, he prefers freelance and consultancy engagements where he can own end-to-end delivery and architecture. An understated detail: beyond product work he actively contributes to the OpenNebula community, combining entrepreneurial drive with open-source stewardship.
14 years of coding experience
7 years of employment as a software developer
Light current engineering, Light current engineering at Secondary technical school LeviceIT, IT at Banking Institute College, Prague
English, Slovak, Czech
Stackoverflow
76reputation
1kreached
7answers
1question
Github Skills (32)
javascript10
docker10
mysql10
dockers10
php10
vlan10
virtualization10
opennebula10
docker-compose9
dns9
go9
python8
smtpd8
postfix-notation8
ruby8
Programming languages (13)
Github contributions (5)
mailcow/mailcow-dockerized
Dec 2017 - Dec 2022
mailcow: dockerized - 🐮 + 🐋 = 💕
Role in this project:
Back-end Developer & DevOps Engineer
Back-end Developer & DevOps EngineerContributions:13 reviews, 61 commits, 79 PRs in 5 years
Contributions summary:Kristián primarily contributed to the mailcow-dockerized project by enhancing backend functionality and improving the user interface. They worked on features like domain alias management, sync job enhancements, and DNS diagnostics, utilizing PHP and related web technologies. Additionally, the user made adjustments to the Docker configurations, including code related to quarantine notifications, demonstrating DevOps skills. They also implemented API improvements.
sogodovecotdisposablemailboxdockerized
OpenNebula/one
May 2017 - Oct 2022
The open source Cloud & Edge Computing Platform bringing real freedom to your Enterprise Cloud 🚀
Role in this project:Back-end Developer & DevOps Engineer
Back-end Developer & DevOps EngineerContributions:1 review, 28 commits, 23 PRs in 5 years 6 months
Contributions summary:Kristián primarily contributed to the OpenNebula platform by fixing bugs and enhancing existing features. Their work includes fixing issues related to VLAN drivers, Docker-machine, and Sunstone. They also added functionalities, such as the option to configure VM logs location, and made enhancements to the Docker-machine, optimizing the API calls. Furthermore, the user addressed issues with time calculations within the Sunstone charters and fixed an IP6 address display bug in Sunstone.
gcpvirtualizationvdiedge-computingvms
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