Hiring: Research Engineer, Post-Training (All Industry Levels) Company: Character.ai Location: San Francisco Bay Area Job Posted Time: 2026-09-09 17:59:13 Employment Type: Full-time Target Skills & Keywords: Post-Training, Fine-Tuning, Alignment Algorithms, Loss Functions, Data Pipelines, Data Infrastructure, GPUs, Reinforcement Learning, Transformers, Distributed Training, ML Deployment, Kubernetes, Docker, Cloud, A/B Testing, Production Code, Large Language Models Experience: - At least PhD (or equivalent) for "All Industry Levels" - Experience working with GPUs (training, serving, debugging) - Experience with data pipelines and data infrastructure - Track-record of exceptional research or creative applied ML projects Required Skills: - Write clear and clean production-facing and training code - Strong understanding of modern machine learning techniques (reinforcement learning, transformers, etc) - Develop alignment algorithms and loss functions to improve data sample efficiency - Write data pipelines to process diverse web data into a format models can ingest - Identify quality signals to understand model performance in the real world - Design sampling algorithms to improve serving efficiency of large generative models Qualifications: - PhD (or equivalent) - Strong understanding of modern machine learning techniques (reinforcement learning, transformers, etc) - Experience working with GPUs (training, serving, debugging) - Experience with data pipelines and data infrastructure - Track-record of exceptional research or creative applied ML projects Nice to Have: - Experience with product experimentation and A/B testing - Experience training large models in a distributed setting - Familiarity with ML deployment and orchestration (Kubernetes, Docker, cloud) - Publications in relevant academic journals or conferences in the field of machine learning Compensation: Not specified in the job posting. Interested candidates, please apply directly through the job posting on company's career page or try via AI auto apply on this platform. Don’t miss this opportunity to join a forward-thinking team!