Senior Java Backend Developer (Spring Boot / Quarkus / API)

About the role

Requirements

• - 5+ years of experience in Java backend development
• - Strong hands-on experience with Spring Boot and Quarkus
• - Solid understanding of microservices architecture
• - Familiarity with API security and performance optimization
• - Java 11+ specifically (not just "Java backend development")
• - OpenShift alongside Kubernetes (currently only Docker/K8s is nice-to-have — should move to required)
• - Proficiency with Git and CI/CD tools (Jenkins, GitLab CI)
• - Working knowledge of SQL/NoSQL databases
• Nice to Have
• - Experience in Open Banking or financial services domain
• - Knowledge of OAuth2, JWT authentication
• - Hands-on experience with Docker, Kubernetes, and cloud platforms (AWS, Azure, or GCP)
• - Apache Kafka or other messaging/event-streaming platforms
• - Observability tools — Prometheus, Grafana, ELK
• Why Join Us
• - Opportunity to work on scalable, enterprise-level systems
• - Collaborative and growth-focused environment
• - Exposure to modern technologies and architecture
• Disclaimer
• This job description outlines the primary responsibilities and qualifications for the role at the time of posting. It is not exhaustive and may evolve in line with business needs and project requirements. CodeNinja reserves the right to modify role scope as the engagement progresses.
• All candidates will be subject to standard background verification. Onsite positions require compliance with the client's site access, security, and NDA policies. CodeNinja is an equal opportunity employer and welcomes applications from all qualified individuals regardless of background.

Responsibilities

• Design, develop, and maintain scalable microservices using Spring Boot and/ Quarkus
• Build, publish, and manage APIs using IBM API Connect (APIC)
• Ensure high performance, security, and scalability of backend systems and APIs
• Collaborate with cross-functional teams including product, QA, and DevOps
• Troubleshoot, debug, and resolve production issues efficiently
• Follow best practices for clean code, testing, and system design
• Containerize applications using Docker and deploy on Kubernetes/OpenShift
• Implement authentication/authorization using OAuth2/JWT standards
• Write unit, integration, and contract tests
• Collaborate with DevOps on CI/CD pipelines
• Participate in code reviews, design discussions, Agile ceremonies
• Monitor, troubleshoot, and optimize microservices performance in production

Skills

• Java backend development
• Spring Boot
• Quarkus
• OpenShift
• Kubernetes
• Docker
• API development
• OAuth2
• JWT
• CI/CD (Jenkins, GitLab CI)
• SQL
• NoSQL
• Git
• API security
• API performance optimization