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, and CI/CD

, Collaborate with product managers, data scientists, and analysts to translate business needs into scalable technical solutions

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