Requirements

- 3+ years of industry experience applying machine learning methods, with a strong focus on recommender systems, search, ranking, or personalization,
- Strong proficiency in Python for production ML systems,
- Experience with A/B testing and experimentation frameworks to measure model impact,
- Familiarity with cloud platforms (AWS, GCP, or Azure) and containerized environments,
- Familiarity with SQL and NoSQL databases,
- Degree in computer science, machine learning, statistics, or equivalent work experience

What the job involves
- We are looking for a Senior Machine Learning Engineer to join our Personalization team in Barcelona,
- You will design and build systems that deliver highly relevant, personalized experiences across our digital products,
- This role sits at the intersection of backend engineering, data, and applied AI—leveraging modern architectures and machine learning techniques to connect users with the most relevant content,
- You will play a key role in building scalable indexing, retrieval and ranking systems that serve personalized content to millions of readers in real time,
- You will partner closely with product, data science,



and engineering teams, bringing technical depth and sound judgment to architectural decisions, model design, and evaluation methodology,
- Design, build, and operate personalization systems and services powering content discovery and user engagement,
- Develop and improve ML models across the whole personalization stack, from candidate generation to final ranking,
- Use data-driven methods to improve candidate retrieval, leveraging embeddings, two-tower architectures, xcskxlj and user/content signals,
- Drive experimentation and A/B testing to measure impact and iterate on models and features,
- Leverage LLMs to enhance content understanding and feature extraction,
- Optimize systems for performance, latency, and scalability across high-traffic environments,
- Contribute to engineering best practices, including testing, observability, and CI/CD,
- Collaborate with product managers, data scientists, and analysts to translate business needs into scalable technical solutions

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📌 Senior ML Engineer, Personalization & Content Ranking (Barcelona)
🏢 Dow Jones
📍 Barcelona