Job Description
Build Japan's Payment Future with ML & Functional Programming
Company Profile A rapidly growing fintech company transforming digital commerce in Japan is seeking a Product Engineer. The platform processes millions of transactions using proprietary machine learning models to enable seamless online shopping experiences. Backed by major global payment companies and leading financial institutions, the organization combines innovative technology with enterprise stability. The engineering team represents 40+ nationalities working in English, maintaining a casual, collaborative culture at their central Tokyo office.
The Role - Architect and scale payment platform components while maintaining security, resilience, and maintainability standards for high-volume transaction processing
- Collaborate directly with product teams to translate business objectives into technical solutions, communicating design tradeoffs clearly across engineering and product stakeholders
- Work cross-functionally in feature teams to deliver services that directly impact user acquisition and conversion rates
- Participate in systematic code reviews and maintain testing practices that ensure production-grade quality for mission-critical payment infrastructure
- Stay current with industry patterns and suggest performance improvements based on data-driven insights from real-world payment flows
- Navigate ambiguity with sound judgment while defining deliverables and maintaining urgency for business-critical releases
Your Skills
Essential Requirements:
- Proficiency in Scala (or strong in functional programming like Rust, Haskell, C++) with curiosity about functional programming paradigms
- Strong grasp of software architecture, design patterns, and how they align with distributed service structures
- Experience writing clean, maintainable code with systematic debugging approaches and automated testing mindset
- Understanding of security implications across distributed systems and payment infrastructure
- Comfortable reading unfamiliar codebases and making intelligent inferences about broader system context
- Genuine interest in how engineering strategy connects to product development and business growth
Bonus Experience (Not Required but Valued):
- Hands-on experience with Scala, Cassandra, Kafka, PostgreSQL, AWS (Fargate/Terraform), or functional programming libraries (cats, cats-effect)
- Background in microservices architecture, event sourcing, CQRS patterns, or REST API design
- Previous work on payment platforms, distributed systems, or fintech products
- Understanding of cross-team dependencies and ability to envision technical roadmaps
Key Highlights of the Role
- Solve genuine technical challenges at scale. Building payment infrastructure that underwrites real-time transactions using proprietary ML models for major e-commerce platforms
- Work with a modern functional programming stack (Scala, cats-effect, tagless final) alongside distributed systems technologies like Kafka, Cassandra, and event sourcing architectures
- Join a truly international engineering team where English is the working language and colleagues represent 40+ nationalities - rare opportunity for Tokyo tech roles
- Shape technology evolution in a well-funded organization transitioning from startup agility to enterprise scale
- Enjoy genuine work-life balance with full flextime (no core hours), up to 3 days remote per week and generous paid time off (20+ days from first year)
- Competitive compensation package with comprehensive retirement programs and premium central Tokyo office access
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