Senior Platform Engineer (Defence & Security)

Reaktor’s tech community is looking for a Senior Platform Engineer to join our Defence & Security Business Unit in Helsinki.

Our Defence & Security Unit brings together around 70 professionals working on technically demanding and societally meaningful projects. Here, you can take ownership of important technical decisions and build systems whose reliability and security genuinely matter.

We are looking for someone who enjoys designing and building large-scale on-premise and private cloud platforms. If you love working hands-on with IaC, CI/CD, security, and observability to solve complex infrastructure challenges alongside product teams and clients, you might be a great fit

Your role is to turn complex, security-critical infrastructure into a reliable platform that development teams can build on.

You will design, build and operate on-premise infrastructure and private cloud platforms that support critical products and our clients’ business needs.

You will be part of both a consulting team working closely with the client and a productisation team bringing solutions to international markets. The role combines hands-on engineering, collaboration and technical decision-making.

Your daily tasks include:

• Designing, implementing and maintaining modern on-premise and private cloud environments, including GPU-enabled infrastructure for AI workloads, to help product teams deliver high-quality solutions.
• Making sure security, isolation, and compliance are built into everything you create.
• Enabling scalable and resilient infrastructure that can grow with demand and keep the digital services running reliably on physical hardware and virtualization layers.
• Automating as many routine tasks as possible to free up engineers time to focus on higher-value work.
• Promoting standardization through common tools, processes and configurations to reduce complexity, improve maintainability, and accelerate development cycles.
• Acting as a trusted advisor by working closely with product teams and other stakeholders to understand the requirements and provide the infrastructure support they need.
• Supporting Reaktor’s Defence & Security Business Unit with sales and proposal work as an infrastructure expert.

You enjoy turning complex, fragmented infrastructure into streamlined, scalable platforms that let teams move quickly and reliably.

What we are looking for:

• Hands-on experience in platform/ infra/ DevOps roles. We don’t have a hard limit with years of experience, but we’ve noticed that these competencies often take 8+ years to accumulate.
• Deep expertise in on-premise infrastructure, including production experience with virtualization technologies (e.g., VMware vSphere, KVM, OpenStack), networking, firewalls, IAM, and hardware-level monitoring.
• Experience with at least one IaC/configuration management tool applicable to bare-metal or private clouds (e.g. Terraform, Ansible, SaltStack, Puppet)
• Solid scripting / programming skills for automation (e.g. Python/Bash/PowerShell)
• Strong understanding of application architectures, container orchestration (e.g., Kubernetes, OpenShift), and the ability to read and reason about code to debug platform issues
• Experience implementing strict security best practices in air-gapped or highly regulated environments following industry standards and compliance
• Fluency in both Finnish and English (written & spoken)
• Willingness to work 100% on-site
• This position requires Finnish citizenship due to client and security regulations. The selected candidate must successfully complete a security clearance process.

Nice-to-have skills:

• Strong CI/CD experience (e.g. GitLab CI, Jenkins, GitHub Enterprise Server or similar)
• Practical experience with self-hosted observability stacks (e.g. Prometheus, Grafana, ELK/Opensearch)
• Customer oriented mindset, with experience in partnering closely with clients/ stakeholders.

While working at Reaktor, we’ll provide you with:

• The ability to impact how you work. Together with the client, your team chooses the approach, technologies, and methodologies you think will work best in any given situation
• A community with as much support as your heart desires
• A team that’s not only experienced but considerate as well – they all want you to succeed
• A sustainable work-life balance and support for your daily life outside of work. (e.g., free moving day, Reaktor car share, sick child care services, office space to use for your private events, etc.)
• An opportunity to grow as a professional. In addition to the day-to-day work, we offer internal training courses, community events to discuss hot topics in tech and design
• Many different hobby clubs, from winter swimming and running to knitting and archery, that bring people together outside of (and sometimes inside) office hours. Many of these are supported by Reaktor