Senior Data Scientist / AI Engineer

Descripción del empleo

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 

Requisitos

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!

Information requirements regarding the collection of your personal data

The entity responsible for processing the information provided in your application is the company specified in the job advertisement, with its registered office at the address indicated therein. The company processes your personal data for the purpose of establishing an employment relationship, in accordance with Article 6(1)(b) of the GDPR / Section 26(1), sentence 1 of the BDSG.

The retention period for your personal data is determined by the applicable statutory retention periods in the relevant country, which begin once the recruitment process has been completed. Further information can be found here.

You may contact the company’s Data Protection Officer at the postal address mentioned above or by email.

Further information about data protection and your rights can be found here.

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Requisitos de información relativos a la recogida de sus datos personales:

La entidad responsable del tratamiento de la información facilitada en su solicitud es la empresa indicada en la oferta de empleo, con domicilio social en la dirección indicada. La empresa trata sus datos con el fin de establecer una relación laboral, de conformidad con el artículo 6, apartado 1, letra b) del RGPD / artículo 26, apartado 1, frase 1 de la BDSG.

El plazo de conservación de sus datos viene determinado por los plazos legales aplicables en el país correspondiente, que comienzan una vez finalizado el proceso de selección. Puede consultarlos aquí.

Puede ponerse en contacto con el delegado de protección de datos de la empresa en la dirección postal mencionada anteriormente o por correo electrónico. 

Puede encontrar más información sobre la protección de datos y sus derechos aquí. Requisitos de información relativos a la recogida de sus datos personales.

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