Senior Data Scientist / AI Engineer

At Penguin Random House Grupo Editorial, we are driven by a twofold purpose: to safeguard the future of books and reading. To achieve this, we publish books for readers of all ages and in a variety of formats, including print, digital, and audio.

We are the Spanish-language division of the international publishing company Penguin Random House and part of Bertelsmann, a global media, services, and education company operating in more than 50 countries worldwide. We are home to 61 publishing imprints, 45 Nobel Prize winners in our catalogue, and more than 20,000 authors.

At the heart of everything we do is a people-centred culture. We value every employee as an individual and foster an inclusive and diverse workplace where everyone feels heard, respected, and valued. We encourage creativity, collaboration, and continuous learning, providing people with the tools and support they need to reach their full potential.

About the team

Our Data Science team builds products that help Penguin Random House make smarter, ethical and commercially responsible decisions. We combine data science, machine learning and the latest developments in AI to solve real business problems and turn promising ideas into tools people can actually use.

Based in Barcelona, you’ll be part of a global Data Science & AI community, collaborating closely with colleagues in the US and across Penguin Random House to share technology, ideas and best practices.

About the role

As a Senior Data Scientist – Applied AI, you’ll take complex problems from exploration and experimentation through to production. You’ll work across machine learning, NLP and generative AI, selecting and evaluating the right approaches to build effective, reliable solutions.

You’ll bring strong Python and data science skills alongside hands-on experience with modern AI, including LLMs, retrieval and agents. You’ll also work closely with ML and Infrastructure Engineers to ensure the solutions you build are reliable, scalable and maintainable in production.

As a senior member of the team, you’ll be expected to make sound technical decisions, challenge assumptions, support other Data Scientists and help shape the approaches and technologies we adopt.

We also care deeply about responsible AI. You’ll consider privacy, security, provenance, model limitations and appropriate human oversight as part of how solutions are designed and built.

What you’ll be doing

• Lead data science and applied AI work from exploration and experimentation through to production
• Develop and evaluate machine learning, NLP and generative AI solutions, selecting the approach that best fits the problem
• Build applications using LLMs and techniques such as 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 capabilities into real products and workflows
• Design experiments and evaluation frameworks to compare approaches, measure quality and understand where systems succeed and fail
• 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
• Work directly with colleagues across the business to turn open-ended questions into practical technical solutions
• Support other Data Scientists and contribute to shared technical standards, reusable components and best practices
• Collaborate with Data Science & AI colleagues globally, while staying current with developments in machine learning and AI and helping identify which new approaches are worth adopting

What you’ll bring

Essential

• 5+ years of professional experience in data science, machine learning, applied AI or a related technical discipline
• Advanced Python skills and the software engineering practices needed to build maintainable production code
• Strong foundations in machine learning and data science, including model development, experimentation and evaluation
• Practical experience building with large language models and generative AI
• Understanding of modern LLM application patterns, including prompting, structured outputs, embeddings, retrieval/RAG and tool or function calling
• Experience designing robust approaches to model evaluation and interpreting results critically
• Strong SQL and experience working with substantial datasets
• Experience with cloud environments and modern data platforms
• Experience building or integrating APIs, services or data pipelines
• The ability to move comfortably between experimentation and engineering, rather than stopping at a successful notebook or proof of concept
• Strong problem-solving skills and the confidence to make technical decisions when the path isn’t obvious
• The ability to communicate clearly with both technical and non-technical colleagues
• A high level of professional English, as much of your collaboration will be with international teams

Nice to have

• Production experience with agents or multi-step LLM systems
• Experience with frameworks such as PydanticAI, DSPy, LangChain/LangGraph or provider-specific agent SDKs
• Familiarity with LLM evaluation, tracing and observability tools
• Experience with AWS
• Experience with Snowflake and/or Databricks
• Experience with Docker, Kubernetes and CI/CD
• Experience building applications using FastAPI, TypeScript, React or similar technologies
• Knowledge of information retrieval, semantic search and vector databases
• Understanding of AI-specific security risks such as prompt injection, inappropriate tool access and data leakage
• Experience mentoring other technical colleagues or contributing to technical standards
• Basic or conversational Spanish

Información adicional

How we work

This position is based in Barcelona and follows a hybrid working model.

You’ll be part of an international team, working closely with US-based leadership and colleagues across Penguin Random House globally.

What do we offer?

• A flexible working culture, with a 50% remote working model
• Offices located in the city centre
• Reduced working hours on Fridays, days before public holidays, and during the summer months
• Company mobile phone
• Access to our e-book and audiobook app
• More annual leave than required under the applicable collective agreement
• Meal vouchers
• Discounts on company products
• … And much more!