Test Engineer

OneSource Consulting; Brussel; On-site; EUR 70,000 - 95,000; Full time

Job summary

OneSource Consulting is seeking an experienced Test Engineer to join a major eDossier modernization program for the Belgian public sector. This is a hands-on engineering role focused on building robust test automation for APIs, UI, and contracts.

You will work with microservices and cloud-native environments, perform performance, regression and integration testing, and contribute to end-to-end test strategies in a multi-language environment (English plus Dutch or French).

Qualifications

• A relevant Bachelor’s or Master’s degree in Computer Science is mandatory.
• 10+ years of overall IT experience with 5+ years in hands-on Test Automation.
• Strong experience with APIs, microservices and cloud-native environments.
• English required with very good Dutch or French.
• Hands-on role; leaders/managers are not suitable.

Responsibilities

• Hands-on testing across API and UI in a modernization program.
• Develop and execute test automation for APIs, UI, and contracts.
• Performance, load and stress testing with relevant tools.
• Execute E2E, regression, and integration tests across components.

Skills

Test Automation

API Testing

UI Automation

JUnit

Cucumber

Performance Testing

SQL

Maven

Monitoring/Observability

Education

Bachelor's or Master's in Computer Science

Tools

Bruno

Cypress

JMeter

Gatling

Grafana

Maven

Job description

Contract: 01/12/2026 – 30/11/2027, with potential extension

We are looking for an experienced, hands-on Test Engineer to join a major eDossier modernization programme in the Belgian public sector.

Key Skills Required10+ years of overall

IT experience 5+ years of hands-on Test Automation

API Testing – preferably Bruno

UI Automation – preferably Cypress

JUnit / Cucumber

JMeter /Gatling for performance, stress amp; load testing

E2E, regression amp; integration testing

Maven

Contract testing, mocking amp; service virtualization

SQL

Grafana / Monitoring amp; Observability

Strong experience with APIs, microservices and cloud-native environments

Good to Have

Event-driven architecture

BDD / DDD

Cloud, API and microservice architecture

Experience within the Belgian/Federal Government environment

Languages Excellent: English plus very good Dutch or French is required.

Important: This is a genuinely hands-on engineering role. Candidates looking exclusively for Lead/Manager/Advisory positions are not suitable.

A relevant Bachelors or Masters degree in Computer Science is mandatory.