Leyton CognitX, the AI & Technology consulting arm of Leyton Group, is expanding its team of 200+ AI & Tech experts into Spain. We are looking for a Lead AI Engineer to provide technical leadership on AI missions for major international accounts, from prototype to production, at the head of a multidisciplinary team. What you will do
• Lead AI missions technically: architecture, roadmap, estimates and delivery from prototype to production
• Lead and mentor the team
• Act as the senior client counterpart on technical decisions and trade-offs
• Contribute to pre-sales
• Design and oversee solutions based on RAG pipelines, LLM agents and model integration (OpenAI, Anthropic, open-source)
• Ensure quality through code reviews with SOLID, design patterns and clean code, plus unit and integration tests and TDD
• Ensure reliable deployments through CI/CD (Git flow, PR reviews) What we are looking for
• 7+ years of experience, including 2+ years leading a team or workstream
• Experience running LLM systems in production at scale: evaluation, observability, cost and latency control, and resilient architectures (async processing, queues, caching, multi-provider fallback); event-driven experience (Kafka, RabbitMQ) is a plus.
• Expert in software engineering, LLM & GenAI (LLM APIs, prompt engineering, RAG, agents, evaluation), backend, APIs & data (REST, GraphQL,



gRPC, SQL and NoSQL, pipelines, search) and architecture, leadership & client delivery (system design, mentoring)
• Advanced in DevOps & cloud (CI/CD, Docker, Kubernetes, AWS / Azure, monitoring)
• Master’s degree or engineering school in Computer Science, Mathematics or Data Science, or equivalent
• Fluent English (client interactions and code reviews)
•

Location:
Sant Cugat del Vallés Tech stack (tech agnostic: no stack is a deal-breaker) Python, TypeScript / Node.js, Java / Spring, FastAPI, React, Angular, Next.js
· LangChain, LangGraph, RAG (chunking, embeddings, vector stores), FAISS, Elasticsearch, PyTorch, TensorFlow, Hugging Face
· PostgreSQL, Redis, MongoDB, Django, Kafka / RabbitMQ, GraphQL, gRPC, Docker, Kubernetes, Jenkins, Terraform, Ansible, GitHub Actions, AWS / Azure

What we offer
• Technical leadership of high-value missions with major international clients
• Autonomy and a voice in architecture, roadmap and pre-sales decisions
• A dynamic, collaborative environment that encourages innovation and experimentation
• Growth and greater responsibility within an international organization
• A high-performance culture: regular feedback, continuous improvement and a focus on delivering tangible value

📌 Lead AI Engineer (San Cugat del Vallés)
🏢 Leyton CognitX
📍 San Cugat del Vallés