We are seeking an experienced Staff Data Scientist with deep expertise in experimentation and ML frameworks (specifically search systems and recommendation engines) to join our dynamic team. Domain knowledge with large language models (LLMs) and post-training optimization is a key priority as we expand our AI capabilities.
Our ideal candidate combines deep technical expertise in search and recommendations with practical experience in LLM systems, bringing a data-driven approach to improving user experiences through better content discovery and model performance.
Design and implement search retrieval and ranking algorithms that surface the most relevant content to users
Develop and optimize recommendation systems for personalized content discovery
Support post-training optimization of LLMs through techniques like RLHF and DPO
Create comprehensive offline evaluation frameworks to measure LLM performance, search quality, and recommendation relevance
Design and execute online A/B testing initiatives to validate improvements across search, recommendations and LLM systems
Drive continuous improvement in model behavior through quantitative analysis and user feedback
Collaborate with engineering teams to implement and productionize algorithms
You could be a great fit if you:
Have 5+ years of experience at chat, social media, or consumer product companies, with substantial focus on ML frameworks
Have deep expertise in testing, optimizing and measuring Large Language Models, search ranking algorithms, recommendation systems
Able to design, drive and execute leaning into high velocity experimentation across consumer facing features
Have a strong intuition for choosing the right questions to ask and quickly driving to key insights, particularly in evaluation of LLM, search and recommendation models and user engagement metrics
Have extensive history of taking ownership and driving impact through data
Advanced degree in Computer Science, Statistics, Mathematics, Engineering or related field
Strong programming skills in SQL, Python and experience with ML frameworks
Strong background in retrieval, ranking algorithms, and relevance metrics
Experience with modern search technologies (e.g., Elasticsearch, vector search) and recommendation frameworks
Expertise in A/B testing and causal inference
Excellent communication skills and ability to collaborate cross-functionally
Working knowledge of LLM architectures, fine-tuning and optimization techniques
Work experience at an AI-centric product company
Familiarity with prompt engineering and LLM offline and online evaluation frameworks
Founded in 2021, Character is a leading AI company offering personalized experiences through customizable AI 'Characters.' As one of the most widely used AI platforms worldwide, Character enables users to interact with AI tailored to their unique needs and preferences.
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.
Ready to shape 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.
Join Character.AI as a Staff Data Scientist and immerse yourself in the exciting world of AI as we expand our capabilities! In this role, you will leverage your deep expertise in experimentation and machine learning frameworks, focusing on advanced systems such as search and recommendation engines. You'll be at the forefront of optimizing large language models (LLMs) while ensuring our users enjoy the best possible content discovery experience. As part of a dynamic team, you’ll design and implement sophisticated search retrieval algorithms and develop personalized recommendation systems that make our platform a game-changer in AI technology. Your technical skills will shine as you support the post-training optimization of LLMs, utilizing techniques like Reinforcement Learning from Human Feedback (RLHF) and Direct Preference Optimization (DPO). But that's not all! You’ll also create robust offline evaluation frameworks that assess LLM performance and conduct A/B testing initiatives to validate improvements. Your analytical mindset will drive continuous enhancement in our AI models, ensuring they align perfectly with user feedback. If you have at least 5 years of experience in chat, social media, or consumer product companies focusing on ML frameworks, and possess an advanced degree in Computer Science, Statistics, or related fields, this could be your perfect role. Join us and be part of a company that has rapidly gained recognition, having achieved unicorn status in just two years. Let's shape the future of consumer AI together!
Character.ai is a neural language model chatbot service provider based in California that leverages sophisticated language models to facilitate conversations with users. Our mobile app had over 1.7 million downloads within its first week in 2023.
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