Research Engineer (Safety and Alignment), Post-Training

Joining us as a Safety and Alignment Research Engineer on the Post-Training team, you’ll be building tools to align our models and making sure they meet the highest standards of safety in the real world.

As increasingly powerful AI models get deployed, building tools to align and steer them becomes increasingly important. Your work will directly contribute to our groundbreaking advancements in AI, helping shape an era where technology is not just a tool, but a companion in our daily lives. At Character.AI, your talent, creativity, and expertise will not just be valued—they will be the catalyst for change in an AI-driven future.

About the role

The Post-Training team is responsible for developing our powerful pretrained language models into intelligent, engaging, and aligned products.

As a Post-Training Researcher focused on Safety and Alignment, you will work across teams and our technical stack to improve our model performance. You will get to shape the conversational experience enjoyed by millions of users per day. This will involve close partnership with our Policy, Research, and Data teams and deploying your changes directly to the product.

Example projects:

• Develop and apply preference alignment algorithms to guide model generations.

• Train classifiers to identify model failure modes and adversarial usage.

• Work with annotators and red-teamers to produce useful datasets for alignment.

• Invent new techniques for guiding model behavior.

Job Requirements

• 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 (reinforcement learning, transformers, etc)

• Track-record of exceptional research or creative applied ML projects

Nice to Have

• Experience developing safety systems for UGC/consumer content platforms

• Experience working on LLM alignment 

• Publications in relevant academic journals or conferences in the fields of machine learning or recommendation systems

Ready to empower the world with AGI? 🚀

Founded in 2021 by AI pioneers Noam Shazeer and Daniel De Freitas, Character is a full-stack AI powerhouse and ranks among the most utilized AI research platforms globally. Our innovative approach allows users to customize their experience with personalized AI 'Characters.'

In just two years, we achieved unicorn status and were named Google Play's AI App of the Year – a testament to our groundbreaking technology and vision.

Noam co-invented core LLM tech and was recently honored as one of TIME's 100 Most Influential in AI. Daniel created LaMDA, the breakthrough conversational AI now powering Google's Bard.

We encourage you to apply even if you don’t meet all qualifications. Underrepresented individuals often experience imposter syndrome—don’t underestimate yourself.

Our commitment to diversity:
Character values diversity and welcomes applicants of all backgrounds. We are an equal opportunity employer and firmly uphold a non-discrimination policy based on race, religion, national origin, gender, sexual orientation, age, veteran status, or disability. Your unique perspectives are vital to us.