About Reaktor

Reaktor is a global creative technology partner that helps industry leaders build a better future. Founded in Finland, we combine premium software engineering, strategic design, and robust data capabilities to solve high-stakes business challenges for global brands like Adidas and Finnair, as well as major enterprises in Japan.

At Reaktor, we have no traditional hierarchy or middle management. We operate on a foundation of absolute trust, immense autonomy, and a shared passion for high-quality engineering.

Our Culture & Philosophy

Autonomy & Responsibility: Two sides of the same coin. We don't manage people; we trust you to think and act independently to make the best decisions. However, this high degree of freedom means you take full ownership and responsibility for the outcomes.
"Do first, apologize later": We value action over hesitation. Instead of waiting for a perfect plan while stalling progress, we encourage experimenting, taking the initiative, and learning fast from the results.

The Role: Senior Technical Lead

As a Senior Technical Lead at Reaktor Japan, you will be the cornerstone of our engineering excellence and agile delivery. You will work closely with our clients, leading cross-functional teams to architecture and implement robust, scalable systems.

We are a technology-agnostic company—we don’t stick to a single stack. Instead, we select the best tools for the specific business problem. You will cross boundaries between frontend, backend, and DevOps as required by the project.

Our Recent Tech Stacks & Tools:

Web: TypeScript, React
Mobile: iOS (Swift + UIKit/SwiftUI)
Backend: Node.js, Golang, PostgreSQL, Redis, Nginx
Infrastructure: AWS, Azure, GCP, Akamai, Terraform, Jenkins
Tools: Git/GitHub, Miro, Docker

What We Are Looking For

Language Proficiency: Native or native-level Japanese fluency is mandatory. Deep understanding of Japanese business culture and high-context communication styles is required to lead client-facing engagements successfully. (Professional English proficiency is a big plus for collaborating with our global teams).
Deep Architectural & Code Understanding: A proven track record of knowing what constitutes high-quality design and clean code, combined with hands-on implementation skills.
Continuous Learning Mindset: A proactive drive to learn new technologies independently and constantly update your skill set.
Strongly Preferred Skills:
- Deep understanding or experience with Functional Programming.
- Capability to design complex system architectures.
- Experience in advanced test design (Unit, Integration, E2E).

What We Offer

True Autonomy: The freedom to shape your own career, choose your tools, and drive projects forward without being micromanaged.
Impactful Work: Opportunities to lead high-stakes digital transformations for major local and global brands.
Premium Environment: A modern, collaborative office space in Ebisu, Tokyo.
Comprehensive Benefits: 20 days of paid annual leave, comprehensive health insurance, mental health and multi-lingual counseling support, and continuous learning budgets.

Our Interview Process (What to expect)

Casual Sync: An introductory chat to share mutual expectations.
Attitude & Soft Skills Interview: A conversational dive conducted by the Japan team (in Japanese) focusing on cultural alignment, autonomy, and collaboration styles.
Technical Round / Design Assignment: An interactive, workshop-style architectural discussion with two of our local developers.

Senior Technical Lead