Expert Test Engineer

Expert Test Engineer - 12 months - Brussels Belgium

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About the Role

RELYzIT Talent is seeking an Expert Test Engineer for a high-impact, freelance assignment with our client, a federal administration at the forefront of digital transformation. This is a 12-month freelance position based in Brussels, with the possibility of extension. You will join a mission-driven team modernizing critical systems that protect vulnerable populations, directly shaping the future of digital public services. Your expertise will be pivotal in ensuring the quality, security, and reliability of a next-generation eDossier platform, built on cloud-native, microservices, and zero-trust principles.

Why This Role Matters

Our client is undergoing a major modernization initiative to deliver secure, robust, and scalable digital solutions for international protection processes. As an Expert Test Engineer, you will be instrumental in guaranteeing that the eDossier solution meets the highest standards of quality and trust. Your work will directly impact the integrity of services relied upon by thousands, ensuring that every release is resilient, performant, and secure. This is a builder’s role: hands-on, outcome-driven, and essential to the mission’s success.

Key Responsibilities

• Design, implement, and manage comprehensive test strategies and operational test plans tailored to a cloud-native, microservices-based environment.


• Develop and maintain automated test suites for business and technical validation, ensuring rapid feedback within CI/CD pipelines.


• Lead functional testing: validate business logic in microservices and APIs, ensure data integrity, and execute end-to-end user flow tests.


• Drive API testing: validate API contracts (OpenAPI), functionality, performance, security, and compatibility between microservices and external systems, with a focus on automation.


• Execute integration testing: test interactions between microservices, COTS components, and external APIs, including error scenario simulations for system resilience.


• Conduct security testing in a zero-trust context, focusing on authentication, authorization, and encryption.


• Perform performance, stress, and load testing of microservices, APIs, and the overall solution.


• Set up and manage monitoring and observability (preferably with Grafana) across development, test, and acceptance environments.


• Collaborate closely with engineers, analysts, and business stakeholders in an agile, cross-functional team.


• Continuously update and share knowledge of new tools, practices, and sustainable trends in cloud-native engineering and testing.


• Participate actively in all sprint events, contributing technical expertise and guidance to ensure robust, secure solutions.


• Propose alternative solutions and recommendations, considering the full technical and business context.

Technical Skills & Experience

• Minimum 10 years of hands-on experience as a Test Engineer, with at least 5 years directly implementing, integrating, and using test automation and monitoring solutions.


• Degree in computer science (higher education, short or long type) is mandatory; diploma must be provided upon application.


• Hands-on experience with monitoring and observability tools, preferably Grafana (5 years).


• Hands-on experience with test automation frameworks and tools (5 years).


• Programming experience with Java SE10+ (3 years).


• Proficiency in scripting languages: Python and JavaScript (5 years).


• Experience with API test frameworks and tools, preferably BRUNO (5 years).


• Experience with UI test frameworks and tools, preferably Cypress, with strong HTML DOM knowledge (5 years).


• Experience with regression and integration testing, preferably JUnit and Cucumber (5 years).


• Experience with performance, stress, and load testing, preferably JMeter and Gatling (5 years).


• Experience with end-to-end (E2E) testing (5 years).


• Experience with build tools, preferably Maven (5 years).


• Experience setting up and integrating tests into CI/CD pipelines, preferably Azure DevOps (5 years).


• Experience with contract testing, mocking, and service virtualization (5 years).


• Experience using SQL databases within testing (3 years).


• Experience working within agile delivery teams (5 years).


• Added value: experience with API design/definition, microservices development/integration, cloud/software design (API, microservice, event-driven), event-driven or behavioral-driven development, domain-driven design, and knowledge of federal government IT building blocks.

Language Proficiency

• Excellent command of English (spoken and written).


• Very good knowledge of Dutch or French (spoken and written) is required due to the bilingual working environment.

Other Requirements

• Freelance position: 12-month contract, renewable upon positive evaluation, with on-site presence required 3 days per week in Brussels.


• Strong ownership mentality: you are hands-on, proactive, and thrive in a builder-first environment.


• Excellent communication skills, able to engage both technical and non-technical stakeholders.


• Team player with a positive, can-do attitude and a passion for IT and quality delivery.


• Not suitable for those seeking purely advisory or lead roles, or for those requiring 4 days of remote work.