Senior Software Tester (AI Test-Aware) - C

About Proximus NXT

Proximus NXT Luxembourg supports all organizations in their digital transformation, by providing holistic ICT & Telecommunication solutions, as well as tailored managed services. With our partners and customers, we co-create opportunities and enable growth in a secure and sustainable manner. As a result of our unique expertise in next-gen IT services, mobile and advanced connectivity, we help our customers achieve their ambitions and realize their vision.

Together with them and our partners we implement sovereign and trusted solutions that make people work smarter.– www.proximusnxt.lu

Your mission :

Senior Software tester with 10+ years of experience Python-based backend systems, AI/LLM pipelines, and automated testing infrastructure. Capable of owning quality assurance across the full stack.
 

WORKING METHODS, ENVIRONMENT AND CONDITIONS

Service delivery: 
The services shall be performed remotely in near-site location within EU territory only.
Laptop will be provided by the Commission and must be collected in Bruxelles 
Onsite presence may be requested with a notice period of 7 days.
• Laptop will be provided by the Commission. 
Applicable security procedures: 
• All non-EU external service providers, who may have access either to EC premises or to EC network,  are subject of security screening by Commission’s security directorate (HR.DS) before specific 
contract signature to assess risks vis-à-vis Commission’s sensitive non-classified information. 
Invoices and reporting: 
• The invoicing will be based on the effective number of days performed indicated in the Monthly  registration report. The monthly registration report shall be addressed to project manager or team 
leader and will be accepted only if a detailed report is provided demonstrating the effort breakdown  per activity or project carried out by the external service provider. 
• Final report to be submitted with the last invoice, including the description of the work carried out  and the results obtained during the execution of the specific contract.

Your profile :

Software Testing
• 10+ years Python background development: async patterns, package design, CLI tooling, REST/gRPC APIs
• FastAPI or equivalent for backend service testing
• Containerized deployments with Kubernetes
• Knowledge on CI/CD pipeline (GitHub Actions, GitLab CI)
 

Testing & Quality Assurance
• Authoring and maintaining automated test suites with pytest (fixtures, parametrize, asyncio)
• Browser and API end-to-end testing with Playwright
• Contract and integration testing for REST and gRPC APIs
• Flaky test detection and remediation
• E2E coverage across UI, API layer, and AI pipeline execution
 

Observability & Metrics
• OpenTelemetry instrumentation within application code (traces, metrics, logs)
• Latency threshold assertions integrated into automated tests
• Experience with Jaeger, Grafana, or equivalent observability stacks
 

End-to-End Ownership
• Full lifecycle coverage: from API entry point through AI pipeline to validated response
• Auth flow testing (SSO, token-based access)
• Failure injection and resilience testing (timeouts, malformed inputs, empty results)
• Containerized E2E test environments mirroring production topology
 

Deliverables Expected
• Automated test suites with >80% critical path coverage
• E2E test plans covering user flows, edge cases, and failure modes
• Trace-based regression reports for AI pipeline runs
• Documentation link to testing: test cases and testing strategy
 

Methodology and Tools
• Experience in the use of Atlassian collaborative tools (like Confluence and Jira) is required
• Experience with Agile development methodologies is a plus
• Experience in working with the EU institutions is a plus

Our offer :

A professional and stimulating work environment in the IT & telecom sector. Multiple career opportunities within the Proximus Group at national and international level, cutting-edge training in new technologies, a wealth of recognized expertise. We also offer an attractive salary package and many other benefits.

Our company is an equal opportunity employer, valuing diversity in all its forms. We firmly believe that each individual brings a unique richness to our teams, and we are committed to creating an inclusive environment where every voice counts.

If at the end of the process your application is successful, you will be asked to provide an extract from your criminal record. Your personal information will be handled in compliance with applicable data protection laws.