Principal Research Engineer (AI)

TL;DR

Principal Research Engineer (AI): Driving the technical vision and execution of post-training systems to transform foundation models into immersive role-playing products with an accent on alignment algorithms and large-scale infrastructure. Focus on optimizing OSS LLMs, developing reinforcement learning methodologies, and building scalable data pipelines for model performance.

Location: Redwood City, CA (Onsite)

Salary: $275K – $400K

Company

AI entertainment platform empowering millions to connect, learn, and tell stories through interactive AI characters.

What you will do

• Define and drive the technical roadmap for mid- and post-training systems, balancing innovation with production reliability.
• Lead the development of alignment algorithms, RL, and preference optimization to improve model capabilities.
• Design scalable training and inference systems for large-scale generative models.
• Architect data pipelines to transform diverse data sources into high-quality training datasets.
• Mentor and grow a team of researchers and engineers through technical guidance and design reviews.
• Optimize distributed training, GPU utilization, and serving efficiency in partnership with infrastructure teams.

Requirements

• PhD in Computer Science, ML, AI, or equivalent industry experience.
• Significant experience leading technical projects in machine learning or large-scale distributed systems.
• Deep understanding of transformers, reinforcement learning, alignment methods, and LLMs.
• Track record of delivering impactful research or applied ML systems in production environments.
• Expertise in training, debugging, and optimizing large-scale models on GPU-based systems.
• Must be based in or able to work in Redwood City, CA.

Nice to have

• Hands-on experience adapting open-source models like Mistral and Qwen for specific personas or role-playing.
• Familiarity with cloud-native ML infrastructure, including Kubernetes and Docker.
• Publications in leading ML conferences or contributions to the AI community.

Culture & Benefits

• Top-notch health coverage for employees and their families.
• Generous 401(k) contribution to invest in your future.
• Incredible paid parental leave of up to 20 weeks.
• 4 weeks of PTO for recharging and exploration.
• Daily in-office catering and a monthly Doordash stipend.
• Monthly wellness stipend to support health journeys.