Senior Backend Software Engineer (m/f/n)

The role supports a long-term eDelivery project for an organization of the European Commission.

• At least 8 years of experience in backend development with Java, Jakarta EE, Spring, Spring Boot, and Hibernate.
• At least 7 years of experience with build tools Maven, Gradle, and npm.
• At least 5 years working with relational databases Oracle DB, PostgreSQL, and MySQL.
• At least 5 years of experience with REST APIs and/or SOAP/WSDL web services.
• At least 5 years working with message brokers ActiveMQ, RabbitMQ, and Kafka.
• At least 5 years experience with message formats and standards: XML, XSD, XPath, WSDL, JSON, JSON Schema.
• At least 5 years using Git with workflows like GitFlow and trunk-based development.
• At least 1 year experience with distributed transaction patterns including idempotency and eventual consistency.
• Experience designing and developing distributed systems and enterprise integrations.
• Experience implementing reliable message delivery semantics.
• Experience with API authentication and authorization.
• Experience with secure API design and application security best practices.
• Experience with service discovery, load balancing, circuit breakers, and inter-service communication.
• Experience designing and operating messaging infrastructures including queue and dead-letter handling.
• Experience with database design strategies including partitioning, sharding, replication, and migration.
• Experience writing unit and integration tests and integrating them in CI/CD pipelines.
• Experience producing technical documentation.
• English proficiency minimum B2 level.

Nice to have:

• Experience with eDelivery standards: OASIS ebMS3, AS4, SMP, BDXL, ebCore PartyId (2+ years preferred).
• Experience with security technologies: TLS/SSL, mTLS, PKI (2+ years preferred).
• Experience with Docker and containerization (2+ years preferred).
• JVM profiling and performance optimization knowledge.
• Experience with secure web application and API technologies: HTTPS, WS-Security, OAuth 2.0, OpenID Connect, JWT, SAML, OWASP practices.
• Experience with Liquibase and zero-downtime database migrations.
• Experience with code reviews, SonarQube, and technical debt management.
• Experience with Python and/or Node.js.
• Experience with enterprise integration protocols and messaging patterns.
• Experience with secrets management solutions: HashiCorp Vault, AWS Secrets Manager.
• Experience with monitoring and observability tools: Dynatrace, Splunk, Elastic APM, OpenTelemetry.
• Experience with CI/CD platforms: Bamboo, GitLab CI, GitHub Actions.
• Experience with infrastructure-as-code tools: Terraform, Ansible.
• Java software architecture and/or enterprise software development certifications.
• Experience working for European institutions, public administration, or large international organizations.
• Experience working with technical standards.
• French language skills (B2+) considered an advantage.

• Build and develop backend services using Java, Jakarta EE, Spring, Spring Boot, and Hibernate.
• Manage builds and dependencies using Maven, Gradle, and npm.
• Design and maintain relational databases including Oracle DB, PostgreSQL, and MySQL.
• Develop and maintain REST APIs and/or SOAP/WSDL web services.
• Design and operate messaging infrastructures using brokers like ActiveMQ, RabbitMQ, and Kafka.
• Implement distributed transaction patterns ensuring idempotency and eventual consistency.
• Develop reliable message delivery with at-least-once or exactly-once semantics.
• Implement authentication and authorization mechanisms for APIs and services.
• Apply secure API design and application security best practices.
• Use patterns for service discovery, load balancing, circuit breakers, and inter-service communication.
• Handle queue management, topics, and dead-letter handling in messaging systems.
• Manage database design, partitioning, sharding, replication, and migration strategies.
• Write unit and integration tests, integrating them into CI/CD pipelines.
• Produce technical documentation.

Services must be performed from within the EU. Occasional travel to Brussels may be required with prior notice. On-site presence is possible upon request with 7 days' notice.