Hybrid Senior Backend Developer

at Reaktor

• Job title: Senior Backend Developer
• Job type: Full Time
• Experience level: Senior
• Salary: Not specified
• Degree requirement: Bachelor's Degree
• Tech skills: AWS, Cloud, Java, Kotlin, Node.js, Python, Scala, Go
• Location requirements: Hybrid, Helsinki, Finland

About the role

• Senior Backend Developer at Reaktor building impactful backends for large-scale consumer solutions. Collaborating with teams to design high-performance services in a hybrid work environment.

Responsibilities

• Design and build high-performance backend services and data pipelines for large-scale consumer products.
• Write clean, efficient code and drive engineering excellence through active code reviews and discussions.
• Take full responsibility for your code in production, from initial design to monitoring, troubleshooting, and continuous performance tuning.
• Work in an autonomous team alongside designers and stakeholders to turn complex business problems into scalable software.

Requirements

• Senior level competency: We don’t have a hard limit on years, but we’ve noticed the strategic eye and architectural depth needed for this role usually take time to accumulate (e.g. 10+ years of hands-on experience).
• A proven track record of building and running large-scale production systems where performance and fault tolerance are critical.
• Deep understanding of the challenges in data-intensive backend work, including comfort with data platform services, frameworks, and pipelines.
• Strong hands-on experience with 2-3 of these backend stacks: Node, JVM (Kotlin, Java, Scala), Python, and Go combined with cloud environments like AWS.
• Experience working on complex consumer solutions where reliability and performance directly impact a massive user base.
• A proactive approach to problem-solving where you prioritize solving challenges as a team and in coding hands-on.
• Consultative mindset and comfortability working in close collaboration with clients and non-technical stakeholders to bridge technical execution with business goals.
• Fluent verbal and written English skills, Finnish skills are seen as an advantage
• Readiness to work in a hybrid-model, min. 2-3 days/week at our or client’s Helsinki office.

Benefits

• To be able 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, and 15-minute coffee breaks to discuss hot topics in tech and design
• A possibility to take part in more extended academy-like studies like Cloud Academy
• 300+ 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