Research Engineer – AI Safety, Alignment

Character.AI

Research Engineer tackling AI safety and alignment at Character.AI. Bridging theoretical research and practical application in AI safety to protect users and assist scientific community.

Posted 4/15/2026full-timeRedwood City • California • 🇺🇸 United StatesMid-LevelSenior💰 $225,000 - $400,000 per yearWebsite

Tech Stack

Tools & technologies

CloudDockerKubernetes

About the role

Key responsibilities & impact

Develop and implement novel evaluation methodologies and metrics to assess the safety and alignment of large language models.
Research and develop cutting-edge techniques for model alignment, value learning, and interpretability.
Conduct adversarial testing to proactively uncover potential vulnerabilities and failure modes in our models.
Analyze and mitigate biases, toxicity, and other harmful behaviors in large language models through techniques like reinforcement learning from human feedback (RLHF) and fine-tuning.
Collaborate with engineering and product teams to translate safety research into practical, scalable solutions and best practices.
Stay abreast of the latest advancements in AI safety research and contribute to the academic community through publications and presentations.

Requirements

What you’ll need

Hold a PhD (or equivalent experience) in a relevant field such as Computer Science, Machine Learning, or a related discipline.
Write clear and clean production-facing and training code
Experience working with GPUs (training, serving, debugging)
Experience with data pipelines and data infrastructure
Strong understanding of modern machine learning techniques, particularly transformers and reinforcement learning, with a focus on their safety implications.
Are passionate about the responsible development of AI and dedicated to solving complex safety challenges.
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), Experience with explainable AI (XAI) and interpretability techniques, Have research in AI safety, alignment, ethics, or a related area, Knowledge of the broader societal and ethical implications of AI, including policy and governance, Publications in relevant academic journals or conferences in the field of machine learning

Benefits

Comp & perks

Top-notch health coverage for you & your family, with majority of the premium covered
We invest in your future with a generous 401(K) contribution
New parents, we've got you covered with incredible paid leave -up to 20 weeks
4 weeks of PTO to explore, unwind & come back recharged
Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are
Monthly wellness stipend to support you in your health journey

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

evaluation methodologiesmodel alignmentvalue learninginterpretabilityadversarial testingreinforcement learningfine-tuningtransformersdata pipelinesmachine learning techniques

Soft Skills

collaborationcommunicationpassion for responsible AI developmentproblem-solvingdedication to safety challenges

Certifications

PhD in Computer SciencePhD in Machine Learning