Senior Java Developer - API Gateway @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 Gateway team builds and operates ING's enterprise API Gateway - a bank-wide, solution that serves as the central entry point for all customer, employee, and third-party facing traffic across ING's global estate. The platform handles inbound and outbound routing, authentication, load balancing, TLS termination, domain circuit-breaking, and front-end hosting for dozens of ING units worldwide. This is critical infrastructure: every digital interaction with ING - mobile banking, web applications, third-party integrations, and internal tools - flows through the API Gateway.

Your Day-to-Day

As a Senior Software Engineer on the API Gateway team you will:

• Design, build, and maintain the gateway platform components - including configuration controllers, domain circuit breakers, and routing services - that power ING's inbound and outbound API traffic across internet and intranet facing domains;
• Develop and extend NGINX-based gateway configurations and custom modules to support Touchpoint API Gateway, Integration Gateway, Outbound Gateway, and front-end hosting use cases;
• Automate operations by building tooling around the automation framework for resource management, configuration deployment, and release train orchestration (production deploys twice per week);
• Ensure reliability and availability of a globally critical service, implementing resilience patterns such as circuit breakers, canary deployments, and DDoS mitigation across multiple data centers;
• Collaborate across squads with platform engineers, SREs, security teams, and consuming product teams to onboard new domains, troubleshoot issues, and define gateway standards;
• Handle incident management including P1/P2 priority incidents, emergency production changes, and post mortem analysis;
• Contribute to the CI/CD pipeline, ensuring automated testing, configuration validation, and safe rollout of changes across dev, test, acceptance and production environments.

Technology Stack

• Languages: Java, Python, Bash, Rego;
• Infrastructure: ING Private Cloud, OpenShift, Linux;
• Configuration & Orchestration: Automation Framework, Azure DevOps CI/CD;
• Observability: Grafana, Prometheus, ELK stack;
• Security: OAuth 2.0, JWT, ING Authentication solution, Zero Trust principles.

What You'll Bring to the Team

Required

• 5+ years of hands-on software engineering experience, with a strong track record in building and operating distributed systems or platform/infrastructure products;
• Proficiency in Java. Experience with Go, Python, C, Bash is a plus.
• Familiarity with containerisation and orchestration (Kubernetes, Docker) and CI/CD pipelines;
• Knowledge of NGINX (configuration, modules, reverse proxy patterns) or comparable API gateway / proxy technologies (e.g., Envoy, HAProxy, Kong);
• Good understanding of networking fundamentals: HTTP/HTTPS, TLS/mTLS, DNS, load balancing, firewalls, and DMZ architectures;
• Strong debugging and incident response skills - comfortable operating under pressure during P1/P2 incidents;
• Excellent communication and collaboration skills; ability to work effectively in a cross-functional, globally distributed team.

Preferred

• Experience building or operating API gateways at scale in a large enterprise or financial services environment;
• Knowledge of authentication & authorisation protocols: OAuth 2.0, OpenID Connect, JWT, SAML;
• Familiarity with observability tooling (Grafana, Prometheus, ELK) and SRE practices (SLOs, error budgets, on-call);
• Experience with high-availability and disaster recovery patterns across multi-data center setups.

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