We are seeking a Senior AI Engineer to join our innovative team in Luxembourg. In this role, you will lead the development and optimization of cutting-edge AI solutions, focusing on large language models (LLMs), retrieval-augmented generation (RAG) systems, and advanced ranking algorithms. Your expertise will drive the creation of scalable, efficient, and domain-specific AI applications that enhance our product offerings and user experiences.

Key Responsibilities:

• Architect and fine-tune open-source LLMs (e.g., LLaMA, Mistral, Falcon) using techniques such as LoRA, QLoRA, and DPO for domain-specific tasks like CV parsing and automated job-description generation.
• Design small-parameter, generalist language models optimized for efficiency, adaptability, and deployment scalability across multiple product use cases.
• Build advanced matching and ranking systems using hybrid retrieval pipelines (e.g., Vespa) orchestrated in Python with LangGraph to generate Top-K candidate matches for job roles.
• Develop Learning-to-Rank (LTR) pipelines (e.g., XGBoost LambdaMART) for candidate re-ranking and relevance scoring.
• Implement retrieval-augmented generation (RAG) pipelines integrating vector search engines such as FAISS, Pinecone, ChromaDB, or Elasticsearch.
• Build and deploy scalable APIs using Python frameworks like FastAPI or Flask.
• Optimize model performance through techniques such as quantization, pruning, and distillation.
• Design and implement efficient ETL pipelines and data-preprocessing workflows in Python, integrating SQL/NoSQL data sources (PostgreSQL, Microsoft SQL Server).
• Leverage cloud and DevOps tools (e.g., AWS, Docker, GitHub Actions, MLflow) for reproducible and scalable deployments.
• Monitor and improve retrieval and ranking quality through feature engineering, embedding evaluation, and offline metrics analysis (NDCG, Recall@K, Precision@K).
• Contribute to technical discussions, code reviews, and the continuous improvement of model-development workflows.

Requirements:

• Master’s degree in Artificial Intelligence, Data Science, Computer Science, or a related field.
• 1–3 years of professional experience in AI/ML engineering, data engineering, or a related area.
• Strong programming skills in Python.
• Hands-on experience with fine-tuning LLMs (e.g., LLaMA, Mistral) and parameter-efficient tuning methods (LoRA, QLoRA, DPO).
• Proficiency in Transformers and NLP libraries (e.g., Hugging Face, LangChain).
• Experience with deep learning frameworks (e.g., PyTorch, TensorFlow).
• Knowledge of API development using FastAPI or Flask.
• Expertise in vector search and RAG systems (e.g., FAISS, Pinecone, ChromaDB, Elasticsearch).
• Familiarity with SQL and ETL pipelines (e.g., PostgreSQL, Microsoft SQL Server, pandas).
• Experience with cloud platforms and DevOps tools (e.g., AWS, Docker, GitHub Actions, MLflow).
• Proven ability to deploy, optimize, and scale machine learning models.
• Excellent communication skills in English.
• Availability for a full-time, hybrid position based in Luxembourg.

Nice to Have:

• Cloud certifications such as AWS Solutions Architect – Associate or Google Cloud Associate Cloud Engineer.
• Experience with search and ranking engines (e.g., Vespa) and Learning-to-Rank methods (e.g., LambdaMART).
• Background in computer vision (e.g., YOLO) or generative models (e.g., GANs).
• Scientific publications in machine learning, NLP, or related fields.
• A strong interest in pursuing a PhD program in areas such as LLMs, NLP, or applied machine learning.