Senior Java Engineer – Payment Services

About the role

Technology Oriented is seeking an experienced Senior Java Engineer to rewrite selected payment micro‑services from Go to Java, ensuring reliable transaction processing and data consistency. The role is office‑based and focuses on building robust payment workflows within a distributed micro‑service architecture.

Key responsibilities

• Analyze existing Go‑based payment micro‑services, including transaction flows and failure scenarios.
• Rewrite selected services in Java while preserving business logic and improving reliability.
• Develop idempotent, deduplicated payment workflows with retry and reconciliation mechanisms.
• Design and maintain gRPC interfaces and proto3 contracts, ensuring compatibility with existing Go services.
• Build event‑driven workflows using NATS JetStream, handling acknowledgments, redelivery, and ordering.
• Work with relational databases to guarantee transaction integrity, auditability, and consistency.
• Write comprehensive unit and integration tests covering payment behavior and failure recovery.
• Implement logging, metrics, tracing, and alerts for observability.
• Plan and execute service migrations, including rollout and rollback procedures.
• Collaborate with DevOps on deployment to AWS or GCP using Kubernetes and support operational readiness.

Required profile

• Significant experience developing production backend services in Java.
• Hands‑on experience with payment systems (processing, payouts, refunds, reconciliation).
• Strong understanding of payment reliability concepts such as idempotency and transaction state management.
• Practical experience with microservices, gRPC, Protocol Buffers (proto3) and messaging systems.
• Proficiency with relational databases, SQL and transaction handling.
• Ability to read Go code and translate business logic into Java.
• Experience deploying or supporting services on AWS or GCP and working with Kubernetes.
• Clear communication in English and willingness to work full‑time onsite in the Bucharest/Pipera office.

Required skills

• Java
• Go (code reading)
• gRPC
• Protocol Buffers (proto3)
• NATS JetStream
• Kafka (preferred)
• Spring Boot
• Docker
• Kubernetes
• AWS
• Google Cloud Platform (GCP)
• SQL / Relational databases
• Git
• CI/CD pipelines
• Unit and integration testing

What we offer

• Responsibility for critical payment services with direct business impact.
• Collaboration with company leadership and project stakeholders.
• Opportunity to influence payment service architecture and engineering standards.
• Exposure to multiple industries and modern development technologies.
• Professional growth in an international, multicultural environment.
• Long‑term official employment with stable contract terms.