Senior Backend Developer

Reaktor's award-winning tech community is looking for a Senior Backend Developer to join us in Helsinki.

If you’re a builder who is inspired by clean, scalable backend logic, values a low-hierarchy environment where you can truly own your work, and gets energy from the technical complexity of large-scale consumer solutions, you’ll feel right at home here.

As a Senior Backend Developer, your role is to bridge the gap between technical excellence and strategic business goals by building impactful backends.

Your daily tasks include:

• 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.

You are an experienced backend developer who gets energy from writing great code, improving systems that are already in production, and building new ones that can scale with growth.

To thrive in this position, you’ll need:

• 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.

Why join us?

For two decades, we’ve been developing qualities and capabilities for adapting, reacting, and supporting change – building Reaktor to hold up in a fast-paced environment while ensuring the well-being of our people.

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

• 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

• Check more benefits & perks below

Diversity, equity, and inclusion

Together, we are committed to making Reaktor an environment that embraces and values all of our employees for the whole of who they are. We encourage applicants from all backgrounds to apply, knowing that studies show that members of underrepresented communities don’t apply for jobs unless they fully satisfy all of the requirements. If you're thinking twice about applying for this reason, we invite you to send us your application anyway. You could be just the person we're looking for.

Read more about our DEI work here.

Please apply by Sunday, March 22. We’ll be reviewing applications as they come in, so don’t wait until the last minute to get yours in.

Interested? Drop us a line – We'll be happy to hear from you!

To apply for any roles at Reaktor, you don't need to submit a resume if you don't have one ready, feel free to share your LinkedIn, website, or portfolio instead.

Due to immediate project needs and our hybrid work model, we are looking for candidates who are already based in Finland. Unfortunately, we cannot provide relocation support or visa sponsorship for this position at this time.