Java Developer – API SDK

About the role

ING Hubs Romania, a software development hub serving 24 ING units worldwide, is looking for a Java developer to work on its API SDK. The SDK is a Spring Boot-based framework that forms the foundation of ING's APIs, configuring beans and filters such as service registry integration, a pre-configured HTTP client, security components, logging and metrics, and service mesh connectivity.

Key responsibilities

• Develop and maintain core API SDK components, delivering features focused on security, resilience and observability while keeping backward compatibility.
• Maintain the toolkit components supporting the platform.
• Integrate with ING infrastructure platforms, build connectivity modules and enable service mesh and discovery integration, supporting direct and proxy-based deployments.
• Design user-friendly APIs and configuration interfaces, write documentation and implementation guides, and develop testing tools and reference implementations.
• Support teams adopting the SDK, review and merge community contributions.

Required profile

• 10+ years in Java development.
• Experience with microservices and distributed systems.
• Strong communication and documentation skills.
• Preferred: framework/SDK development experience, Spring Boot, Kafka, API gateways, OpenAPI, PostgreSQL/Cassandra, financial services or regulated environments.

Required skills

• Languages and frameworks: Java 17+, Spring Boot, Scala, Maven, Gradle.
• Platforms: Kubernetes, OpenShift, Docker, Azure DevOps/GitHub.
• Integration: Kafka, REST APIs, service discovery.
• Observability: Prometheus, Grafana, OpenTelemetry, logging platforms.
• Security: PKI, token-based authentication, mTLS, API gateways.
• Core: OAuth2, JWT, microservices, service mesh, resilience patterns, CI/CD.