At Aristocrat, we are advancing gaming technology with modern, powerful solutions. Our mission is to bring happiness to life through play. We value collaboration, creativity, and a strong passion for excellence. These roles primarily support the Machine Learning area of our Product Madness business line — a tech company specialised in social casino mobile games. We are looking for an ML Engineer to join our MLOps team and strengthen its modeling core. You will own machine learning models end to end, from data and experimentation to production, and help us build the monitoring and experimentation culture that keeps them reliable and aligned with the business over time. You will make a real difference in our products and players' experiences.

What You'll Do

- Design, train, evaluate and retrain machine learning models with emphasis on recommender systems — that support game features, player experience, and operational efficiency.
- Own the design of our model performance monitoring: define what to track (drift, data quality, degradation), thresholds, and what “the model is still healthy” means in business terms.
- Help establish a solid experimentation culture: model versioning and experiment tracking with tools such as MLflow or Weights & Biases, so experiments are reproducible and model versions are easy to compare and promote.
- Help establish a model governance culture: define how models are promoted to production and lay the foundations of the communication contract between the MLOps team and Data Science.
- Create templates and cookiecutter scaffolding to standardise how Data Science structures, hands off, and communicates its models and experiments.
- Build robust training and feature-engineering pipelines, and write clean, production-ready Python and SQL.




- Explore and contribute to early-stage projects involving LLMs, RAG and agentic AI where they bring value — as a complement to the role, not its core.
- Develop simple interfaces (e.G., Streamlit) to expose ML capabilities to non-technical users when useful.
- Collaborate with teams across product, data, and engineering, and communicate results, limitations, and recommendations clearly across technical and business audiences.

What We're Looking For

- 4+ years of experience applying machine learning to real-world problems, from data to deployment.
- Proven experience with recommender systems (collaborative filtering, ranking, or similar) applied to real products.
- Strong Python skills and hands-on experience with ML libraries (scikit-learn, PyTorch/TensorFlow, XGBoost or similar).
- Solid SQL expertise and experience working with large data warehouses.
- Hands-on experience with experiment tracking and/or model registry tools (MLflow, Weights & Biases, or equivalent).
- Experience designing or contributing to model monitoring / performance tracking in production.
- Comfort working with cloud platforms (e.G., GCP, AWS, Azure), Docker, and Airflow.
- A strong analytical foundation, with a background in a quantitative field (mathematics, physics, computer science, engineering) or equivalent experience.

Nice to Have

- Experience with Snowflake or similar cloud data warehouses.
- Hands-on experience building applications with Generative AI (LLMs), including API integration.
- Interest or early experience in RAG systems — whether through prototypes, side projects, or professional work.
- Interest or familiarity with agentic AI concepts or frameworks (e.G., LangChain agents, CrewAI).
- Ability to build simple user interfaces (e.G., Streamlit) to expose ML models to wider teams.

📌 Ml Engineer (Barcelona)
🏢 Product Madness Espana
📍 Barcelona