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 No SQL 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, 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,

📌 Senior ml engineer, personalization (Madrid)
🏢 Dow Jones
📍 Madrid