Principal Research Engineer, Post-Training

Character.ai
Redwood City, California
Workplace: OnsiteFull timeUSD 275,000 - 400,000 annuallyFunction: Education & TrainingEducation: phdSkills: ["Leadership","Mentorship","Communication","Collaboration","Problem-solving"]

Lead the post-training ML systems at Character.AI, driving technical vision and execution to transform foundation models into aligned, interactive products. You will oversee data, algorithms, infrastructure, and evaluation, mentoring researchers and engineers, collaborating across teams to improve model performance, safety, and user engagement at scale.

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FursaFursa
Character.ai
Character.ai
2 months ago

Principal Research Engineer, Post-Training

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Canonical indexed version, validated from employer's careers page.

Source: Company careers pageValidated by: Fursa AI
Last checked: 1 hour agoStatus: Live

Job Summary

Lead the post-training ML systems at Character.AI, driving technical vision and execution to transform foundation models into aligned, interactive products. You will oversee data, algorithms, infrastructure, and evaluation, mentoring researchers and engineers, collaborating across teams to improve model performance, safety, and user engagement at scale.
Location: Redwood City, California
Workplace: Onsite
Employment Type: Full time
Job Function: Education & Training
Seniority: Sr. Manager level

Key Responsibilities

  • •Define and drive the technical roadmap for mid- and post-training systems, balancing research innovation with production reliability and scalability, while mentoring a team of researchers and engineers.

Pay and Benefits

Salary: USD 275,000 - 400,000 annually

Key Requirements

  • •PhD in Computer Science, Machine Learning, AI, or a related field, or equivalent industry experience.
Experience:AIMachine learningDistributed systemsOpen sourceLLM
Education:PhD / Doctorate
Skills:LeadershipMentorshipCommunicationCollaborationProblem-solving
Tech Stack:TransformersReinforcement learningAlignmentDistributed trainingGPUKubernetesDocker

Company Brief

Character.ai
Builds a conversational AI platform where users create and interact with lifelike AI characters for entertainment, learning, and productivity, backed by advanced large‑language‑model research and consumer-facing products.
Industry: AI & Machine Learning
Company Size: Medium (51 to 250 employees)
Growth: Scaleup
Valuation: Unicorn (USD 1B+)
Funding: Series A
Headquarters: Menlo Park, United States
Founded: 2021
Glassdoor
Glassdoor: 3.6
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