AI Test Engineer (m/f/d) at SIXT

AI Test Engineer (m/f/d) Company: SIXT Location: Lisbon, Portugal (Hybrid) Department: TECH & Engineering Employment Type: Full-time About SIXT: SIXT is a global mobility leader with EUR 4.00 billion revenue and ~9,000 employees. About the Role: SIXT seeks a QA engineer to test virtual agents and AI-powered customer service workflows. The role combines classical QA expertise with agentic automation and conversational AI knowledge. Key Responsibilities: - Design end-to-end test plans for customer service virtual agents across voice, chat, and email channels - Build and maintain test suites validating autonomous workflows (booking changes, billing, damages) - Define and monitor quality metrics: resolution rate, deflection, CSAT, safety violations - Develop test data and synthetic scenarios for edge cases, ambiguous queries, multilingual requests - Evaluate agent behavior through reasoning traces and tool-use decisions - Implement automated testing frameworks for conversational flows, APIs, integrations - Contribute to LLMOps/CI/CD pipelines for regression detection - Conduct bias, fairness, and safety testing aligned with company policies - Collaborate cross-functionally on requirements and acceptance criteria Required Qualifications: - 2-3 years software QA/test engineering experience - Strong understanding of testing principles: functional, regression, integration, performance - Hands-on experience testing AI/ML systems (LLM chatbots, recommendation engines) - Familiarity with multi-agentic systems, frameworks like LangChain, AWS AgentCore - Python scripting and REST API testing skills - Understanding of LLMOps/MLOps: versioning, monitoring, rollback strategies - Customer service process and KPI experience or interest - Fluent English; German or additional languages preferred Benefits: - 28 vacation days plus birthday day off, 1 volunteer day annually - Hybrid work model with flexible hours, no dress code - SIXT service discounts and partner benefits - Training programs, conferences, internal tech talks - Private health insurance - Coverflex advantage system