ML Engineer (AI)

Location: Barcelona, Spain; hybrid work requiring attendance at the Barcelona office 3 days per week

Company

hirify.global develops mobile gaming experiences and uses data, machine learning, and AI to support player personalization and business decisions.

What you will do

• Build, train, evaluate, and improve machine learning models for prediction, recommendation, personalization, and decision support.
• Develop LLM-powered applications and workflows using query formulation, structured outputs, retrieval-augmented generation, and tool integration.
• Create software components, services, and APIs that add ML and AI capabilities to existing applications.
• Evaluate model performance and AI outputs, identify failure modes, and contribute to testing and evaluation frameworks.
• Deploy, monitor, and maintain ML/AI solutions in production with MLOps Engineers.
• Prepare and validate data, write maintainable Python code and automated tests, and collaborate with Data Scientists, engineers, and product partners.

Requirements

• BSc, MSc, or PhD in Computer Science, Machine Learning, Artificial Intelligence, Mathematics, or a related technical field, or equivalent practical experience.
• 2+ years of professional experience in software engineering, machine learning engineering, or AI development, including practical ML model or AI application development.
• Strong Python skills covering software development, testing, debugging, version control, and collaborative development.
• Hands-on experience developing, training, and evaluating supervised learning models with scikit-learn, PyTorch, TensorFlow, or similar frameworks.
• Experience building LLM applications with query formulation, structured outputs, RAG, and tool calling.
• Understanding of model evaluation methods, performance metrics, and AI output validation.
• Practical experience in at least one specialization: recommender systems, time-series modeling, unsupervised learning, or reinforcement learning.
• Strong SQL skills and experience retrieving, transforming, and validating data from analytical databases and APIs.
• Familiarity with model deployment, inference services, monitoring, ML lifecycle management, cloud platforms, containers, CI/CD pipelines, and ML development environments.

Nice to have

• Experience in mobile gaming, digital entertainment, or large-scale consumer applications.
• Experience developing recommendation or personalization systems.
• Familiarity with agentic workflows, AI agents, or advanced LLM applications.
• Experience with model serving, distributed computing, or performance optimization.
• Experience with managed ML platforms such as Vertex AI.
• Familiarity with Bayesian modeling, causal inference, or simulation techniques.

Culture & Benefits

• Hybrid working model with 3 days per week in the Barcelona office.
• Collaborative work with Data Scientists, engineers, MLOps Engineers, and product collaborators.
• Compensation and benefits may include annual bonuses, incentives, health and wellbeing benefits, paid time off, retirement plans, insurance, and local or statutory benefits, depending on role and location.

Hiring process

• Submit your CV in English.
• Specific compensation details will be discussed during the recruitment process.