{"id":879,"url":"https://alion.io/job/character-ai-research-engineer-post-training-all-industry-levels","title":"Research Engineer, Post-Training (All Industry Levels)","company":{"id":36,"name":"Character.AI","domain":"character.ai","url":"https://alion.io/company/character-ai","size_band":"51-200","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Ashby","truth_index":{"grade":"D","score":40,"open_postings":13,"ghost_share":1,"stale_share":0,"repost_share":0,"time_to_fill_p50_days":null,"computed_at":"2026-10-27T05:46:45Z"}},"role":"AI/ML","role_family":"AI/ML","seniority":null,"employment_type":"full_time","work_mode":"hybrid","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["New York, United States"],"countries":["US"],"hiring_countries":[],"hiring_countries_total":0,"salary":{"min":225000,"max":400000,"currency":"USD","period":"year","gross":null,"usd_annual":400000},"salary_estimate":null,"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Fine-tuning","optional":false},{"name":"Machine Learning","optional":false},{"name":"Post-training","optional":false},{"name":"Reinforcement Learning","optional":false},{"name":"A/B Testing","optional":true},{"name":"Docker","optional":true},{"name":"Kubernetes","optional":true}],"status":"live","first_seen_at":"2024-01-24T05:51:56Z","employer_posted_date":"2024-01-24","last_verified_at":"2026-10-27T07:55:46Z","board_verified":true,"closed_at":null,"days_open":1007,"trust":{"level":"ghost","repost_count":0,"flags":["stale","company_stale"],"days_open":1006},"description":"About the role and team\nJoining 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.\nThe Post-Training team is responsible for developing our powerful pretrained language models into intelligent, engaging, and aligned products.\nAs 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.\nWhat you'll do\nDevelop alignment algorithms and loss functions to improve data sample efficiency.\n\nWrite data pipelines to process diverse web data into a format models can ingest.\n\nIdentify quality signals to understand our model’s performance in the real world.\n\nDesign sampling algorithms to improve serving efficiency of large generative models.\n\nWho you are\n\"All Industry Levels\": have at least PhD (or equivalent)\n\nWrite clear and clean production-facing and training code\n\nExperience working with GPUs (training, serving, debugging)\n\nExperience with data pipelines and data infrastructure\n\nStrong understanding of modern machine learning techniques (reinforcement learning, transformers, etc)\n\nTrack-record of exceptional research or creative applied ML projects\n\nNice to Have\nExperience with product experimentation and A/B testing\n\nExperience training large models in a distributed setting\n\nFamiliarity with ML deployment and orchestration (Kubernetes, Docker, cloud)\n\nPublications in relevant academic journals or conferences in the field of machine learning\n\nAbout Character.AI\nCharacter.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.\nIn 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.\nJoin us and be a part of establishing this new entertainment paradigm while shaping the future of Consumer AI!\nAt 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. 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