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, 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 (Barcelona)
🏢 Dow Jones
📍 Barcelona