Back End Developer

Backend Engineer – Scalable Payment Systems We're hiring a backend engineer to help build high-performance payment infrastructure that delivers fast and reliable experiences to millions of users. Responsibilities: Design and build scalable backend systems for high-throughput applications Work with cloud infrastructure to optimize performance and reliability Own your code from development through production support Contribute to tooling and open-source projects where relevant Tech Stack Highlights: Java / Kotlin / Scala, Spring Boot, Kafka, Redis, MySQL, DynamoDB, Docker, Kubernetes, AWS, GCP, GitHub, Jenkins, BigQuery Requirements: 3+ years of Java experience Solid grasp of algorithms, data structures, and OOP Experience with NoSQL and distributed caching Understanding of concurrency and distributed systems Proficiency in English and Japanese ( business level ) Nice to Have: Experience with APIs, pub/sub, AWS services, or financial systems Familiarity with microservices and high-scale architectures