Senior / Mid LLM Engineer – Applied AI & Model Optimization

Mystery Project

📍 donostia/san sebastián, país vasco, Spain

Full-time Ingeniería y tecnología Posted June 14, 2026

Job Description

Senior / Mid LLM Engineer – Applied AI & Model Optimization (San Sebastián, Spain)

Hybrid

About the opportunity

We are partnering with a fast-scaling deep-tech company operating at the intersection of advanced AI, large language models, and next-generation computational techniques. The team focuses on solving real-world, high-impact problems by building and optimizing AI systems used by global enterprises across industries such as finance, energy, and industrial operations. This is not a pure research role — it’s applied AI at scale, where your work directly translates into production-ready solutions.

Role mission

As an LLM Engineer, you will play a key role in designing, improving, and deploying large language models, with a strong focus on efficiency, scalability, and real-world applicability. You’ll work on challenging problems such as model compression, performance optimization, and integration into complex systems, collaborating with ...