Senior LLM Engineers & Researchers Location: Barcelona, Madrid, Zaragoza, San Sebastian (on-site with some flexibility) We are partnering with a well-funded, rapidly scaling deep-tech company operating at the intersection of advanced AI and next-generation computing to find their next Senior LLM Engineers & Researchers. Their team combines world-class researchers and engineers working on cutting-edge challenges in large-scale LLM model development, optimization, and deployment. This is an opportunity to join a highly technical environment where you will directly contribute to the future of large language models - not just apply them. As a Senior LLM Engineer or Researcher, you will design, train, and optimize large-scale transformer models, contributing across pretraining, post-training alignment (SFT, RLHF, DPO), evaluation, and inference optimization. This is a deeply technical role focused on core model development rather than downstream application or prompt engineering. Key Responsibilities Design and train transformer-based models from scratch,



including large-scale pretraining pipelines Contribute to post-training workflows such as SFT, RLHF, and DPO Build and optimize large-scale data pipelines for training and evaluation Improve model performance through architecture, training, and efficiency optimizations Optimize inference and training performance across GPU/HPC environments Collaborate with engineering teams to deploy models into production systems Mentor junior engineers and contribute to technical best practices Required Experience & Skills Ph D with industry experience since with hands-on experience training transformer or LLM models from scratch Strong understanding of transformers, optimization, and deep learning fundamentals Expertise in Python, Py Torch, and the Hugging Face ecosystem Experience with distributed training frameworks such as Deep Speed, FSDP, or Megatron Experience with inference optimization tools such as v LLM or Tensor RT-LLM Exp

📌 Senior llm engineer (Santander)
🏢 European Tech Recruit
📍 Santander