Senior Backend Engineer | Java
Almere
Full-time
5-10 years experience
Hybrid
Work Arrangement
Office Days per Week: 2 days
Key Skills
Java
Spring Boot
Quarkus
REST API
Kafka
Kubernetes
Docker
PostgreSQL
Hibernate
JPA
CI/CD
Jenkins
GitHub Actions
System Architecture
Technical Leadership
Security Clearance
Job Description
Opportunity
Hybrid (2 days on-site) · Permanent, full-time
About the role
Offline, air-gapped installations for NATO customers mean your API versioning and backward-compatibility decisions are not technical hygiene, they are the difference between a fleet that can operate and one that cannot. The backend services you design and maintain run in constrained, version-locked environments where an incompatible release cannot simply be rolled back over a network connection. Beyond feature delivery, this role carries real technical leadership weight: you will help set Java coding standards, guide architectural decisions, and mentor engineers across the Backend Engineers chapter, with an explicit goal of distributing knowledge rather than concentrating it.
Your Mission
What you'll do
- Design and maintain Java backend services and APIs so they remain stable and versioned across releases, allowing customers in offline environments to upgrade on their own schedule.
- Build and own complex business logic and integration layers connecting to legacy and customer systems, working across REST, SOAP, batch file exchange and event-driven patterns with Kafka.
- Package and deliver services for Kubernetes deployments including offline customer installations, applying reproducible build, image signing and SBOM practices throughout.
- Define and embed Java coding standards, dependency policies, security defaults and testing practices across the chapter, reducing bus-factor risk through shared ownership.
- Contribute to build-or-not decisions alongside product owners, translating technical constraints and integration complexity into options the product team can act on.
- Collaborate with analytics engineers on Python and Spark integrations, and review technical design documents to raise the quality bar across the team.
What success looks like
Over time, the backend services you own become the most dependable part of the platform: APIs hold their contracts across releases, new engineers can read and extend the codebase without escalating to you, and offline deployments ship with a clear, reproducible packaging trail. As your ownership grows, the chapter's standards documents reflect decisions you have driven and stress-tested with domain experts, and build-or-not conversations happen earlier because the team trusts your technical reading of complexity and risk.
What you bring
- 6+ years of professional backend engineering experience with Java as your primary language, and a solid track record across complex, production-grade systems.
- Expert-level Java 17+ with deep knowledge of Spring Boot or Quarkus, and strong JVM internals: garbage collection tuning, memory profiling, heap and thread dump analysis.
- REST API design with OpenAPI, including versioning strategy and backward compatibility across release cycles; strong JPA/Hibernate, JDBC and database migration tooling (Flyway or Liquibase); PostgreSQL query optimisation, indexing, partitioning and large-table migrations.
- Kafka exposure in an production environment
- Good understanding of: Docker, Kubernetes and Helm in production packaging contexts, not only local development; CI/CD pipelines (Jenkins or GitHub Actions); security and quality tooling including SonarQube, dependency scanning, SBOMs and image signing used in a real delivery pipeline.
- Clear written and verbal communication in English with both engineering and product stakeholders; a degree in computer science or software engineering, or equivalent professional experience that demonstrates the same capability.
- Eligibility to obtain and maintain the required national or NATO security clearance for this role (we support candidates through the clearance process).
If you meet most of these criteria, we encourage you to apply. The eligibility requirement for the required security clearance is not flexible.
Nice to have
- Legacy integration depth: Oracle, SQL Server, PL/SQL, SOAP or batch file exchange in production contexts.
- OIDC and Keycloak at the integration and usage level for authentication and authorisation; secrets management, TLS and RBAC; structured logging, metrics and observability tooling (Grafana, OpenSearch or equivalent).
- Air-gapped or offline software delivery experience, particularly using signed bundles or tooling such as Zarf; experience with FIPS mode or STIG-hardened environments is especially relevant given our deployment constraints.
- Advanced Keycloak administration and fine-grained authorisation configuration; reactive or async Java patterns using virtual threads or Project Reactor.
- Experience in regulated or defence-adjacent industries; working knowledge of Dutch or French.
Build Your Future with ILIAS
Why ILIAS Solutions
ILIAS Solutions is part of the Patria Group and builds software that defence operators depend on to plan and execute missions. The platform runs in the environments where failure is not recoverable with a hotfix: offline, air-gapped, version-locked. That context makes correctness and compatibility genuinely consequential, and it makes the engineering choices here matter beyond the sprint.
This is a role for an engineer who finds legacy integration intellectually interesting rather than career-limiting, who wants to set standards rather than just meet them, and who values a codebase they can be proud of over one they are the only person who understands. The working language is English; Dutch or French is useful but not required to do the job well.
Eligibility
Because of the nature of our work, this role may require eligibility under applicable export-control regulations and the ability to obtain national or NATO security clearance. We assess eligibility lawfully and on a role-by-role basis; specific requirements are discussed during the selection process. We do not exclude candidates on the basis of nationality except where mandated by applicable export-control or security-clearance law.
How to apply
Send your CV and a short note on your backend integration experience to the ILIAS Solutions careers page or via the application link on this posting. Questions before you apply? Reach out to Tim van Dam at [email protected], he is happy to tell you more about the role and the clearance process.
About us
In defence operations, timing and reliable information shape every decision. Many organizations still rely on fragmented systems, limiting visibility and slowing execution. ILIAS Solutions connects logistics, maintenance, and operations into one integrated platform. This creates a single source of truth and enables teams to act on real time data across strategic, operational, and tactical levels. Large volumes of operational data move continuously between systems. This data reflects maintenance cycles, logistics flows, and asset readiness. Accuracy and consistency directly impact operational outcomes.Core Responsibilities
Design and maintain stable Java backend services and APIs for offline, air-gapped environments. Lead architectural decisions, set coding standards, and mentor engineers to ensure high-quality, reproducible deployments.
Requirements
Requires 6+ years of professional Java backend experience with expertise in Spring Boot or Quarkus and JVM internals. Candidates must be eligible for national or NATO security clearance and possess strong knowledge of containerization and API versioning.
About ILIAS Solutions
Industry: IT Services and IT Consulting
Company size: 51-200 employees
ILIAS Solutions specializes in information management solutions to support defence and humanitarian aid operations. Our software platforms are centred on the optimisation of operational readiness, and based upon the management of the resources required for those operations. In order to provide our customers with solutions that are tailored to their specific needs, ILIAS Solutions consists of an effective team of experts in the development, implementation and maintenance of software systems, with experience in managing complex and sensitive assets maintenance and logistics systems. Our team can provide you with a wide variety of skills ranging from business analysis, process improvement and project management to software development, testing, training, maintenance, helpdesk services, and much more. ILIAS Solutions is ISO 9001 certified for all activities related to the development, provisioning and maintenance of IT solutions for asset management.
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