Senior Data Scientist / AI Engineer

About the role

Penguin Random House Grupo Editorial, the Spanish-language division of the international publisher Penguin Random House and part of Bertelsmann, is hiring a Senior Data Scientist – Applied AI for its Data Science team in Barcelona. The team builds products that help the group make smarter, ethical and commercially responsible decisions, combining data science, machine learning and AI. The role takes complex problems from exploration and experimentation through to production, working with ML and Infrastructure Engineers and with colleagues in the US and across the group.

Key responsibilities

• Lead data science and applied AI work from exploration and experimentation through to production.
• Develop and evaluate machine learning, NLP and generative AI solutions, choosing the approach that best fits each problem.
• Build applications using LLMs, structured generation, embeddings, semantic search, retrieval, RAG, tool use and agents.
• Develop production-quality Python services, APIs and data pipelines that integrate models and AI into real products.
• Design experiments and evaluation frameworks to compare approaches and measure quality.
• Work with structured and unstructured data at scale using SQL and modern data platforms.
• Collaborate with ML and Infrastructure Engineers on deployment, containerization, monitoring and production operations.
• Support other Data Scientists and help shape the approaches and technologies adopted.
• Consider privacy, security, provenance, model limitations and human oversight in line with responsible AI.

Required profile

• 5+ years of professional experience in data science, machine learning, applied AI or a related technical discipline.
• Strong foundations in machine learning and data science, including model development, experimentation and evaluation.
• Ability to move between experimentation and engineering, and to make technical decisions when the path is unclear.
• Clear communication with technical and non-technical colleagues, and a high level of professional English.

Required skills

• Advanced Python and software engineering practices for production code.
• Practical experience with LLMs and generative AI, including prompting, structured outputs, embeddings, retrieval/RAG and tool/function calling.
• Strong SQL and experience with large datasets.
• Cloud environments and modern data platforms; APIs, services and data pipelines.
• Nice to have: agents or multi-step LLM systems, PydanticAI, DSPy, LangChain/LangGraph, AWS, Snowflake, Databricks, Docker, Kubernetes, CI/CD, FastAPI, TypeScript, React, vector databases, and AI security risks such as prompt injection.

What we offer

• Hybrid working model with 50% remote work.
• Flexible hours, reduced hours on Fridays, days before public holidays and in summer, and more annual leave than required by the collective agreement.
• City centre offices, company mobile phone, e-book and audiobook app access, meal vouchers and discounts on company products.