Senior Java Developer - API SDK Team @ING Hubs Romania

Discover ING Hubs Romania

ING Hubs Romania offers 130 services in software development, data management, non-financial risk & compliance, audit, and retail operations to 24 ING units worldwide, with the help of over 2000 high-performing engineers, risk, and operations professionals.

We started out in 2015 as ING’s software development hub, then steadily expanded our range to include more services and competencies. Now we provide borderless services with bank-wide capabilities and operate from two locations: Bucharest and Cluj-Napoca. 

Our tech capabilities remain the core of our business, with more than 1800 colleagues active in Data and Analytics Tech, Tech Foundation and Channels, Retail Core Banking and Architecture, and Global Products and Technology Services. 

We enjoy a flexible way of working and a highly collaborative environment, where fair and constructive feedback is encouraged.  

For us, impact isn't a perk. It's the driver of our work. We are guided and rewarded by a shared desire to make the world a better place, one innovative solution at a time. Our colleagues make it their job to do impactful things and they love doing it in good company. Do you?  

The Mission

The API SDK is ING's core framework for developing secure, resilient, and high-performance APIs. This role offers the opportunity to work on foundational platforms that power ING's digital banking capabilities across our global technology ecosystem.

API SDK is a Spring Boot-based framework that serves as the foundation for developing APIs. It's a lightweight layer on top of Spring Boot that configures beans and filters specific to the ING landscape, including:

• Service registry integration for automatic service registration and discovery
• Pre-configured resilient HTTP client for inter-service communication
• Security components (token validation, access control, and authorization)
• Centralized logging and metrics integration with monitoring platforms
• Service mesh connectivity and proxy support for polyglot architectures

Your day to day

Framework Development & Maintenance

• Design, develop, and maintain core components of the API SDK;
• Implement new features that enhance security, resilience, and observability;
• Ensure backward compatibility while evolving the framework architecture;
• Create and maintain the Toolkit components that underpin the framework.

Platform Integration

• Integrate with ING's infrastructure platforms (container platforms, messaging systems, API gateways);
• Implement connectivity modules;
• Ensure seamless integration with service mesh and service discovery;
• Support both direct framework usage and proxy-based deployments.

Developer Experience

• Build intuitive APIs and configuration interfaces for framework consumers;
• Create comprehensive documentation, cookbooks, and how-to guides;
• Develop testing toolkits and frameworks for local development and validation;
• Provide reference implementations demonstrating best practices.

Community & Support

• Support development teams using the API SDK through internal support channels;
• Review and merge community pull requests.

Technologies You'll Work With Daily

• Languages & Frameworks: Java 17+, Spring Boot, Jersey, Scala, Maven, Gradle;
• Infrastructure & Platforms: Kubernetes, Docker, Azure Container Registry, Azure DevOps (repos, pipelines, artifacts);
• Integration & Communication: Apache Kafka and enterprise messaging systems, RESTful APIs, Service registry and discovery systems;
• Observability Stack: Prometheus + Grafana, OpenTelemetry and distributed tracing, Enterprise logging and metrics platforms, ;Centralized logging infrastructure
• Security: PKI infrastructure, token-based authentication, mTLS, certificate management, API Gateway technologies.

What you'll bring to the team

Qualifications

• 7+ years of professional Java development experience;
• 3+ years building distributed systems or microservices;
• Bachelor's or Master's degree in Computer Science or equivalent experience;
• Proven track record of designing and building reusable components;
• Experience supporting developer communities or internal platforms;
• Excellent communication skills for technical documentation and support.

Preferred Experience

• Prior experience building frameworks or SDKs consumed by other developers;
• Knowledge of Finagle (Twitter's RPC framework) or similar RPC frameworks;
• Experience with Kafka and event-driven architectures;
• Familiarity with API Gateway patterns and implementations;
• Understanding of microservices architectures in banking or enterprise platforms;
• Experience with OpenAPI/Swagger specification;
• Knowledge of Cassandra, PostgreSQL, or other distributed databases;
• Background in financial services or highly regulated industries.

Core Java & Spring Ecosystem

• Expert-level Java with deep understanding of JVM internals;
• Spring Boot mastery - dependency injection, auto-configuration, actuators;
• Maven build tooling and dependency management.

Distributed Systems & Resilience

• Experience with microservices architecture patterns;
• Knowledge of service mesh concepts and implementations;
• Understanding of circuit breakers, retry patterns, and backpressure;
• Familiarity with distributed tracing (OpenTelemetry).

Security & Compliance

• Understanding of OAuth 2.0, JWT tokens, and PKI infrastructure;
• Experience with mTLS and certificate-based authentication;
• Knowledge of secure coding practices and OWASP standards.

Infrastructure & Deployment

• Experience with containerization (Docker, Kubernetes);
• Knowledge of CI/CD pipelines (preferably Azure DevOps);
• Understanding of deployment strategies (blue-green, canary, rolling updates).

Observability & Monitoring

• Experience with Prometheus metrics and alerting;
• Knowledge of centralized logging (ELK stack or similar);
• Grafana or similar dashboard creation and monitoring;
• Understanding of SLI/SLO/SLA concepts.

If you want to deep dive into the processing of personal data conducted by ING Hubs Romania during the recruitment process and your rights related to it, read the privacy notices on our website (make sure to scroll until you reach the Data Protection section/ Candidates tab). 

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