Machine Learning / AI Engineer (Hybrid Madrid)

• Develop, deploy, and optimize machine learning and AI solutions that address complex business challenges
• Create multi-agent systems and equip AI models with function/tool-calling capabilities
• Design and implement RAG systems to ground AI responses in enterprise data
• Assess and integrate AI models (e.g. LLMs) ensuring optimal performance and reliability
• Optimize agentic workflows and AI agents for production use cases
• Testing and optimizing system prompts and few-shot example to ensure accurate , consistent, and safe AI outputs
• Performance evaluation of machine learning and AI models using appropriate metrics, evaluation sets and techniques, and continuously iterate and improve upon them
• Collaborate with platform teams, data engineers, data scientists, and other stakeholders to integrate machine learning solutions into existing systems and processes
• Participate in code reviews, testing, and debugging to ensure the quality and reliability of machine learning solutions

• Bachelor's or Master's degree in Data Science, Computer Science, Mathematics, Statistics, or a related field
• Strong programming skills in Python with experience in machine learning libraries and deep learning frameworks such as TensorFlow or PyTorch
• Proven experience working with Large Language Models (LLMs)
• Good understanding of AI agents & agentic workflows, LLM orchestration frameworks and reasoning patterns
• Experience with data preprocessing, feature engineering, and model selection and evaluation techniques
• Knowledge of statistical and mathematical concepts relevant to machine learning, such as probability, linear algebra, and optimization
• Understanding software development best practices, including version control, testing, and documentation
• Excellent problem-solving and debugging skills, with the ability to identify and resolve issues quickly and effectively
• Relevant work experience in machine learning, data science or a related field
• Good english level (C1) you will be working with international teams.

Hybrid. Madrid city center (Sol area). 3 days a week in the office + 2 days remote.

Work schedule

Business Hours. No intensive working days for friday or summer.

What can we offer?

• 23 days of Annual Leave plus the 24th and 31st of December as discretionary days!
• Numerous benefits (Health Care Plan, teleworking compensation, Life and Accident Insurances).
• `Retribución Flexible´ Program: (Meals, Kinder Garden, Transport, online English lessons, Health Care Plan…)
• Free access to several training platforms
• Professional stability and career plans
• UST also, compensates referrals from which you could benefit when you refer professionals.
• The option to pick between 12 or 14 payments along the year.
• Real Work Life Balance measures (flexibility, WFH or remote work policy, compacted hours during summertime…)
• UST Club Platform discounts and gym Access discounts

More in details, UST is a multinational company based in North America, certified as a Top Employer and Great Place to Work company with over 35.000 employees all over the world and presence in more than 35 countries. We are leaders on digital technology services, and we provide large-scale technologic solutions to big companies.