San Francisco, CA · San Francisco$200k – $290k
All roles / Character AI / Research Engineer, Post-Training (All Industry Levels)
Research Engineer, Post-Training (All Industry Levels)
Source verified: this exact posting was present on Character AI’s careers feed on . View employer source →
What the posting asks for
- Names
- Kubernetes
- Doctorate
- Named as preferred, or equivalent experience
Read out of the employer's own description. Absence means the posting does not say, not that the answer is no.
The role
About the role and team
Joining us as a Research Engineer on the Post-Training team, you'll be diving into the exciting world of fine-tuning AI models, optimizing their performance, and ensuring they meet the highest standards of quality and efficiency. 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.
The Post-Training team is responsible for developing our powerful pretrained language models into intelligent, engaging, and aligned products.
As a Post-Training Researcher, you will work across teams and our technical stack to improve our model performance and training methods, including data, compute and algorithms. You will get to shape the conversational experience of millions of users per day.
What you'll do
Develop alignment algorithms and loss functions to improve data sample efficiency.
Write data pipelines to process diverse web data into a format models can ingest.
Identify quality signals to understand our model’s performance in the real world.
Design sampling algorithms to improve serving efficiency of large generative models.
Who you are
"All Industry Levels": have at least PhD (or equivalent)
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 with product experimentation and A/B testing
Experience training large models in a distributed setting
Familiarity with ML deployment and orchestration (Kubernetes, Docker, cloud)
Publications in relevant academic journals or conferences in the field of machine learning
About Character.AI
Character.AI empowers people to connect, learn and tell stories through interactive entertainment. Over 20 million people visit Character.AI every month, using our technology to supercharge their creativity and imagination. Our platform lets users engage with tens of millions of characters, enjoy unlimited conversations, and embark on infinite adventures.
In just two years, we achieved unicorn status and were honored as Google Play's AI App of the Year—a testament to our innovative technology and visionary approach.
Join us and be a part of establishing this new entertainment paradigm while shaping the future of Consumer AI!
At Character, we value diversity and welcome applicants from all backgrounds. As an equal opportunity employer, we 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 our success.
Published by Character AI on their own careers page and reproduced here unedited. Read it at Character AI.
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What this listing does not tell you
Listed 989 days, which is longer than most. Of the 40 post-training and RL roles this board has watched from listing to removal, 100% were gone from their employer's careers page by day 989, and the median came down after 110 days. That is a description of other listings that have already ended, not a prediction about this one: this board records when a listing disappears, never why, and a posting still up is not on a clock it can see.
Character AI has 6 roles open on this board, 3 of them in post-training and RL.
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