Staff Data Scientist, Trust & Safety

You'll join Vinted's Trust & Safety domain, whose mission is to protect the Vinted community from harmful activities and content. Across several detection, moderation and sanctioning teams, we run a growing set of machine learning models, rule engines, and LLM agents. They score every new listing, account and message at Vinted's scale, and many of them act on members automatically.

We're looking for a Staff Data Scientist to shape the architecture and effectiveness of our detection systems as a whole. You'll tackle problems that individual teams cannot solve independently: how to maximize detection coverage, combine different models into coherent risk decisions, and allocate computational resources where they reduce the most harm.

This is a senior individual contributor role with scope across Trust & Safety and Security domains. You'll set technical direction, challenge existing approaches, prototype solutions and work with teams to bring them into production.

It's an opportunity to shape how a large-scale, increasingly AI-driven safety system is built, evaluated and improved.

• Design the end-to-end ML architecture for detection, risk scoring, routing and decision-making.
• Develop cost-efficient, layered inference strategies that combine broad, low-latency screening with deeper, more expensive analysis where it adds the most value.
• Establish approaches to continuous risk assessment across the member lifecycle, from registration and listing creation to ongoing activity.
• Define how we measure end-to-end detection effectiveness, including precision, coverage, missed harm and computational cost. Use these measurements to identify the highest-impact improvements.
• Turn siloed, team-level models into a coherent, calibrated detection system by addressing the technical and organisational barriers that lead to local optimisation.
• Identify and close detection coverage gaps, ensuring that relevant signals and outcomes are available for evaluation, diagnosis and continuous improvement.
• Set shared technical standards and architectural direction across teams, working with engineering and data science leaders to translate them into production systems.
• Prototype critical components, test architectural assumptions empirically and build reference implementations that teams can scale.
• Explain complex ML trade-offs to senior technical and business leaders as clear choices about harm reduction, cost, and engineering investment.

• Have 8+ years of experience in Data Science, Machine Learning, or a similar role, including significant time owning production models or model evaluation at scale.
• Have led cross-team technical work without formal authority, and you're comfortable setting standards that other teams adopt.
• Have deep expertise in statistical inference and experimentation: A/B testing, measuring precision and recall under imperfect or biased labels, sampling for ground truth, and causal reasoning.
• Understand the ML lifecycle in production: evaluation, threshold setting, retraining, drift, feature stores and monitoring.
• Have hands-on experience evaluating LLM-based systems, or a strong interest in building rigorous methods for them.
• Are highly proficient in SQL and Python and comfortable working in a modern data stack (e.g. BigQuery, dbt).
• Can turn messy, cross-system problems into a clear plan, and can explain trade-offs to both technical and non-technical audiences, including senior leadership.
• Are fluent in English, both written and spoken.

Nice to have

• Nice to have: experience in Trust & Safety, fraud prevention, content moderation, or risk management.

• The opportunity to benefit from our share options programme
• 25 working days of holiday
• Access to all the tools & tech needed for work
• Home office support: we provide IT workstation equipment and a personal budget of up to 540 for home workplace furniture
• Private health insurance
• Pension plan with flexible contribution options and a matching contribution from Vinted
• Confidential Employee Assistance Program (EAP) for you and your family
• Frequent team-building events
• A personal monthly budget for shopping on Vinted
• A dog-friendly office
• In Vilnius office: Gym & in-house meals at friendly prices
• In Kaunas office: a monthly lunch allowance, and a once-a-week provided in-house lunch and breakfast