Szabolcs Gelencsér, Developer in Budapest, Hungary
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Szabolcs Gelencsér

Verified Expert  in Engineering

Software Developer

Budapest, Hungary
Toptal Member Since
September 24, 2021

Szabolcs is a highly efficient software professional with a passion for learning and a wide range of experience from low-level hardware systems to high-level distributed systems. He's led software teams at both IBM-level enterprises and Bitrise-level startups while also being part of DevOps and infrastructure teams. Szabolcs is looking forward to contributing to the front end, back end, and DevOps on diverse and exciting projects.


Go, Kubernetes, Nomad, Ansible, Terraform, Docker, Heroku, PostgreSQL, Redis...
CMO24 Zrt. and & prodHost Ltd.
Kubernetes, Azure, Azure DevOps, Terraform, Python, Docker, Prometheus...
Go, Terraform, Kubernetes, Docker, React, Linux, InfluxDB, GraphQL...




Preferred Environment

Visual Studio Code (VS Code), Git, Windows Subsystem for Linux (WSL)

The most amazing...

...project I've ever worked on is a scheduling system that allows running CI builds on thousands of nodes.

Work Experience

Staff Software Engineer | Technical Lead

2020 - PRESENT
  • Reduced operational maintainability costs, improved build speeds and company gross margin, and enabled a successful series C funding by leading the software development to allow Bitrise's new generation of infrastructure.
  • Enabled a more sophisticated architecture and a successful SOC2 certification by transferring our services from Heroku to Kubernetes as part of a virtual team.
  • Built a performant product team by actively mentoring other engineers and ensured technical best practices by writing and automating policies.
Technologies: Go, Kubernetes, Nomad, Ansible, Terraform, Docker, Heroku, PostgreSQL, Redis, Datadog, Shell Scripting, Google Cloud Platform (GCP), MacOS, Leadership, Scrum, Unit Testing, Integration Testing, E2E Testing

Infrastructure Engineer

2020 - 2020
CMO24 Zrt. and & prodHost Ltd.
  • Enabled go-to-market by designing and creating their staging and production infrastructure from scratch with Terraform on Microsoft Azure, running their test suites, and deploying their microservices to Kubernetes with Azure Pipelines.
  • Reduced development time and MTTD by implementing a Minikube-based local environment, integrating the production deployment manifests.
  • Secured the infrastructure by integrating everything with Active Directory through OAuth (as a single source of truth), applying least privilege policies everywhere with restricted firewalls and VPN.
  • Accelerated incident resolution with Prometheus, Loki, and Alertmanager-based monitoring, logging, and alerting.
  • Handed over the projects for maintenance with learning sessions throughout documentation and ADRs.
Technologies: Kubernetes, Azure, Azure DevOps, Terraform, Python, Docker, Prometheus, Freelancing

Senior Software Engineer | Technical Lead

2019 - 2020
  • Reduced maintenance costs and increased security by automating remote OS upgrades of Linux servers.
  • Enhanced network security by enabling a hierarchical CDN setup, eliminating the need for public internet connection.
  • Improved stability of data collection by migrating its back end from Elasticsearch to InfluxDB.
  • Led the implementation of a public API, enabling our services automation for customers.
Technologies: Go, Terraform, Kubernetes, Docker, React, Linux, InfluxDB, GraphQL, Amazon Web Services (AWS), IBM Cloud, MySQL, Travis CI, Jenkins, Leadership, Kanban, Next.js, Apollo, Express.js, Unit Testing, Integration Testing, E2E Testing

Software Engineer

2018 - 2019
Budapest University of Technology and Economics
  • Enabled the same workflows of the previous on-premise cloud on top of OpenStack, getting the best of both worlds: stability and ease of use.
  • Introduced the cloud to a broader audience and attracted the attention of NIIFI by presenting it at the Networkshop 2018.
  • Allowed general availability by deploying the entire system on a cluster of servers, integrating it with the existing services of the university.
Technologies: Python, OpenStack, Ansible, Docker, Linux

DevOps Engineer

2018 - 2018
  • Led the development of a Python tool that automates the detection of third-party components upon their addition to Balabit's codebase, ensuring legal compliance.
  • Reduced maintenance costs and increased stability of the products by building CI/CD pipelines using GitLab CI/CD and Jenkins.
  • Maintained the development team's infrastructure using SaltStack.
Technologies: Python, GitLab CI/CD, Jenkins, SaltStack, Shell Scripting, Networking, Kanban

Software Engineer

2017 - 2018
  • Eliminated the maintenance costs by implementing a Jenkins plugin in Java.
  • Enabled ad-hoc usage for security engineers by building a management interface with React.
  • Ensured security compliance by writing passive scripts for scanning the network traffic in JSR 223 compatible JavaScript.
Technologies: JavaScript, Java, React, Jenkins, C#, Web Security, Docker

Software Engineer

2016 - 2016
Danubisoft Kft.
  • Simplified the development of products and decreased the time to implement them by enabling C++ developers to construct a responsive HTML5 GUI without specifying exact layouts and sizes for every screen size using an auto-layout algorithm.
  • Enabled the usage of cheap tablets and mobile phones for customers using Danubisoft ERP by implementing a WebSocket-based interface and a thin client.
  • Ensured faster desktop-based products by implementing a thick client with Chromium Embedded Framework. Both the thin and the thick clients are automatically generated without extra development effort.
Technologies: C++, Chromium Embedded Framework (CEF), WebSockets, HTML5

End-to-end Kubernetes Environment

I was hired to design and deploy the production hosting environment for two startups. After one month of part-time work, I was able to deliver 50+ services running in AKS. I documented architectural design decisions, everything was codified with Terraform, and CI/CD pipelines were stably automating their releases.

Next, I've implemented Python-based tooling that hid the complexities of Kubernetes using standardized Helm charts. The last step was bringing the same environment to the developer machine using Minikube, providing the fastest possible feedback to developers.

Since then, they have also increased their revenue by offering the automated infrastructure, DevOps toolchain, and developer environment as a spin-off product.
2013 - 2019

Master's Degree in Software Engineering

Budapest University of Technology and Economics - Budapest, Hungary




Terraform, Git, Ansible, Travis CI, GitLab CI/CD, Jenkins, SaltStack, Helm


Go, Python, JavaScript, Java, C#, C++, C, GraphQL, HTML5


Kubernetes, Docker, Linux, Windows, OpenStack, Heroku, Google Cloud Platform (GCP), Azure, Amazon Web Services (AWS), MacOS, Visual Studio Code (VS Code)


PostgreSQL, Redis, Datadog, InfluxDB, MySQL


Chromium Embedded Framework (CEF), Next.js, Express.js


Agile Software Development, Test-driven Development (TDD), Azure DevOps, Kanban, Scrum, Testing, Unit Testing, E2E Testing


Nomad, Windows Subsystem for Linux (WSL), Shell Scripting, Prometheus, IBM Cloud, Networking, Web Security, WebSockets, Leadership, Freelancing, Apollo, Integration Testing

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