Senior Data Scientist

🚀 Senior Data Scientist | Reinforcement Learning

🌍Athens, Greece - Hybrid

💸€50,00-€65,000

We’re looking for a Senior Data Scientist, with expertise in Reinforcement Learning to help shape the future of our revenue management platform, which processes over 24 million tickets per year. You’ll work at the intersection of machine learning, experimentation, and product, building models that directly impact business outcomes on a massive scale.

What You’ll Do

• Tackle high-impact, ambiguous problems: Collaborate with Product, Engineering, and Design to define metrics, success criteria, and roadmaps.
• Build and ship advanced models: From forecasting and ranking to optimization, clustering, causal inference, and reinforcement learning (RL).
• Work on RL challenges: Formulate MDPs/bandits, design reward functions, implement policies (e.g., DQN, PPO, actor-critic), and run offline evaluations.
• Design rigorous experiments: A/B tests, CUPED, and sequential testing — then translate results into clear business insights.
• Productionize your work: Partner with ML Engineers to deploy services, monitor performance, and manage model retraining cycles.

What We’re Looking For

• 6+ years of experience in Data Science or Applied ML, with a proven record of delivering production models.
• Proven experience with Reinforcement Learning
• Strong foundations in statistics, inference, experimentation, and optimization.
• Expert-level Python (NumPy, Pandas, PyTorch or TensorFlow).
• Experience running and analyzing large-scale online experiments.

Interested? Apply to be considered!