Research Engineer / Scientist, Post-training - Paris

About H: H exists to push the boundaries of superintelligence with agentic AI. By automating complex, multi-step tasks typically performed by humans, AI agents will help unlock full human potential. H is hiring the world’s best AI talent, seeking those who are dedicated as much to building safely and responsibly as to advancing disruptive agentic capabilities. We promote a mindset of openness, learning, and collaboration, where everyone has something to contribute. About the Team: The Models team builds the foundational models that power our cutting-edge agentic technology. We focus on training techniques to optimize model capabilities specifically for agent applications. This allows us to achieve the best performance at a given inference cost. Our work spans the development of Large Language Models (LLMs) and Vision-Language Models (VLMs), enabling agents to perceive, understand, and act within complex environments. We are deeply involved in enhancing these models through training methods with a focus on improved instruction following, tool use, and interaction with dynamic environments via large-scale reinforcement learning and reward modeling. We operate at the intersection of research and product, translating cutting-edge research into practical solutions that drive the next generation of AI. We are looking for bright, motivated individuals to join our ranks and shape the future of superintelligent AI. Key Responsibilities: Develop and train advanced LLMs and VLMs, including multimodal architectures Research and implement training methods for enhanced capabilities like instruction following and tool use Design and optimize data pipelines and training systems for large-scale distributed training Collaborate with cross-functional teams to integrate models into agentic AI systems Evaluate model performance and communicate findings to stakeholders Stay current with advancements in LLMs, VLMs, and related fields Requirements: Technical skills: Strong programming skills (Python, Git) Expertise in deep learning frameworks (PyTorch, JAX, TensorFlow) Experience with large-scale distributed training of LLMs and VLMs Hands-on experience with LLM training, alignment, and reinforcement learning Knowledge of multimodal architectures and applications Research skills: Publications in top-tier AI conferences (e.g., NeurIPS, ICML, CVPR, ACL, ICCV) Advanced degree (PhD or MSc) in a relevant field (e.g., ML, DL, NLP, CV) Soft skills: Excellent communication and presentation skills Strong collaboration and teamwork skills Passion for AI and problem-solving Bonuses: Industry experience Experience in LLM training with RL Experience with data processing techniques Location: Paris or London. This role is hybrid, and you are expected to be in the office 3 days a week on average. Please expect some travel between offices on a reasonable cadence (e.g., every 4-6 weeks). What We Offer: Join the exciting journey of shaping the future of AI, and be part of the early days of one of the hottest AI startups Collaborate with a fun, dynamic and multicultural team, working alongside world-class AI talent in a highly collaborative environment Enjoy a competitive salary Unlock opportunities for professional growth, continuous learning, and career development If you want to change the status quo in AI, join us.