Principal Research Engineer, Post-Training at Character AI
- Company: Character AI
- Location: Redwood City, CA
- Employment type: Full-time
- Salary: $275K – $400K
- Posted: 2026-06-22
About the role
About the Role and Team As a Principal Research Engineer on the Post-Training team, you will drive the technical vision, execution, and evolution of the systems that transform foundation models into intelligent, engaging, and aligned products. Specifically, your team focuses on post-training of top-tier OSS LLMs (such as Mistral and Qwen) to power the highly immersive role-playing chat features of Character.AI http://Character.AI. You will lead initiatives spanning data, algorithms, infrastructure, and evaluation, helping define how our models learn from feedback and improve over time. This is a highly cross-functional role that combines deep technical expertise with organizational leadership. You will partner closely with researchers, engineers, product teams, and infrastructure teams to identify the highest-leverage opportunities for improving model performance and user experience.…
Apply on Character AI's official careers page: https://jobs.ashbyhq.com/character/cab23a8b-97ba-4b20-a8e3-f7d9a61e13f4