Senior AI Engineer - Stealth Mode Start-up - up to £150k - London

🚀 Senior AI Engineer | Stealth Mode AI Start-up 📍 London 💷 Up to £150k OB are currently partnered with a stealth-mode start-up at the forefront of AI research , and they’re looking for a Senior AI Engineer to join the team and work on some genuinely challenging problems across LLMs, reinforcement learning and agentic systems. This is a hands-on research + engineering role, where you’ll be involved in: 🧠 LLM training \& fine-tuning — including reinforcement learning and post-training 🔄 Evaluation \& feedback loops — building systems to continuously assess and optimise models 🤖 Agent development — designing and building sophisticated AI agents 🔬 AI research — exploring LLM training, RL, evaluation and optimisation techniques 💻 Software engineering — strong engineering fundamentals are essential (Python) What they’re looking for: * Strong experience working with LLMs and/or foundation models * Experience with training, fine-tuning, RL or post-training * Background in model evaluation and optimisation * Experience building AI agents / agentic systems * Strong software engineering fundamentals 📍 London – 2 days hybrid 💰 Up to £150k Interested? Apply below for more details Stealth | London | Senior AI Engineer