Application Architect

OneSource Consulting; Brussel Hoofdstad; Hybrid; EUR 70,000 - 110,000; Full time

Job summary

OneSource Consulting in Belgium is seeking seasoned Java professionals to join the CIAO Catena program, strengthening delivery teams for public sector digital services. You will work on development, integration, and evolution of critical systems, contributing to modern software engineering practices.

The role covers architecture design, API development, Agile ceremonies, and collaboration with stakeholders, ensuring security, performance, and interoperability across multi-system environments in

Qualifications

• 7+ years of Java software development experience.
• 5+ years of application architecture experience.
• Experience in complex multi-system environments and large-scale digital transformation.
• Public sector experience is an asset.
• Proven experience in Agile delivery environments.

Responsibilities

• Develop and maintain business applications and shared digital services.
• Develop application components, APIs, and web services.
• Contribute to the design of architecture and building blocks with leads/architects.
• Participate in Agile/Scrum ceremonies and stakeholder meetings.
• Support testing, documentation, deployments, QA, monitoring, and continuous improvement.

Skills

Java development

Application architecture

Agile delivery

Public sector experience

Stakeholder collaboration

Tools

Spring Framework

JPA/Hibernate

RESTful Web Services

Keycloak

Lombok/MapStruct

Angular 20

Maven

Docker

GitLab CI/CD

SonarQube

NPM

OAuth 2.0

Flyway/Liquibase

PostgreSQL

SQL Server

BPMN/UML

Jira/Confluence

CI/CD

Job description

Work Regime: Fulltime | Hybrid (2-3 days onsite per week)

Job Description - Roles and Responsibilities

• As part of the CIAO Catena program, we are looking for consultants to strengthen the existing delivery teams involved in the development, integration, and evolution of critical public sector digital services.
• The CIAO Catena initiative aims to support the digital transformation of public administrations through the implementation of interoperable, secure, and scalable solutions facilitating laboration and information exchange between organizations. The program includes the development of new functionalities, the enhancement of existing platforms, and the adoption of modern software engineering practices.

Key activities include:

• Development and maintenance of business-critical applications and shared services.
• Integration with internal and external systems through APIs and service-oriented architectures.
• Modernization, optimization, and continuous improvement of existing applications and technical platforms.
• Contribution to the implementation of secure and resilient digital services supporting public sector organizations.

Responsibilities

• Development and maintenance of business applications and shared digital services.
• Development of application components, APIs, and web services.
• Contribute to the design of application architecture and technical building blocks in laboration with technical leads and solution architects.
• Participate in technical workshops, Agile/Scrum ceremonies, and stakeholder meetings.
• Support testing activities, technical documentation, deployments, quality assurance, monitoring, reporting, and continuous improvement initiatives.
• Collaborate with multidisciplinary teams to ensure alignment with business and technical requirements.
• Ensure adherence to security, performance, interoperability, and quality standards.
• Code review

Experience

• Minimum 7 years of professional experience in Java software development.
• Minimum 5 years of professional experience in Application architecture
• Experience working in complex multi-system environments and large-scale digital transformation projects.
• Experience in public sector environments is considered an asset.
• Proven experience in Agile delivery environments.

Technical knowledge and practical experience of the following technologies:

• Java >= 21 and Spring Framework (Core, JDBC, Data, Security, AOP)
• JPA / Hibernate
• RESTful Web Services
• Keycloak, Lombok, MapStruct
• Angular 20
• Maven
• Docker
• Git and GitLab CI/CD
• SonarQube
• NPM
• OAuth 2.0
• Flyway or Liquibase
• PostgreSQL, SQL Server and relational databases
• BPMN and UML
• Jira and Confluence
• Continuous Integration and Continuous Delivery (CI/CD)