Character AI

Research Engineer focused on multimodal AI, specifically video and image generation models. The role involves training, fine-tuning, and deploying these models, including joint audio-visual generation and image-to-video. It also includes designing new architectures, optimizing models for inference, and building large-scale data pipelines. The company is a consumer-facing AI platform.

Research Engineer focused on AI safety and alignment for large language models. Responsibilities include developing evaluation methodologies, researching alignment techniques, conducting adversarial testing, mitigating harmful behaviors using RLHF and fine-tuning, and translating research into scalable solutions. Requires a PhD or equivalent, strong coding skills, GPU experience, and understanding of transformers and reinforcement learning with a focus on safety implications.

Research Engineer on the ML Systems team at Character.AI, focusing on optimizing ML training and inference systems, GPU cluster performance, fine-tuning AI models, and serving LLMs at scale. The role involves improving training performance and inference runtime, shaping conversational experiences, and developing systems for multimodal models and distributed RLHF.

Research Engineer on the Post-Training team responsible for fine-tuning AI models, optimizing performance, and ensuring quality and efficiency. Works on alignment algorithms, data pipelines, quality signals, and sampling algorithms for large generative models to shape conversational experiences.

Software Engineer on the AI Platform team at Character.AI, focusing on building tooling and datasets for model training, developing data pipelines for continuous model improvement and human feedback alignment, and supporting data infrastructure (Spark, Beam, GCP). Requires 5+ years of data engineering experience in a consumer-facing tech company, with Big Query, dbt, Ray, Beam, and Spark.

Machine Learning Infrastructure Engineer to design, build, and maintain training and serving infrastructure for ML research, focusing on GPU allocation and utilization, cluster issue diagnosis, and deployment monitoring.

Technical Program Manager for AI Infrastructure at Character.AI, focusing on leading programs for model development and serving systems at scale. This role involves shaping infrastructure strategy, aligning roadmaps, and driving execution across training, evaluation, and inference, ensuring systems are reliable, efficient, and scalable for millions of users. The TPM will partner with engineering, research, and product teams, manage complex initiatives, track key metrics, and improve developer velocity.

Product Manager for Character.AI's core product, focusing on conversations, characters, and creator tools. The role involves translating AI model capabilities into engaging consumer experiences, driving innovation in AI entertainment, and collaborating with research, engineering, and design teams. Success is defined by sustained user engagement and product quality.

Software Engineer, Backend/Applied ML (Safety & Integrity) at Character.AI. Focuses on designing, developing, and scaling backend systems and applying ML to address integrity and safety challenges in human-to-AI interaction, particularly for Generative AI products. Involves content classification, anomaly detection, risk scoring, and developing safeguards.

Software/ML Engineer to build and optimize applied ML models and infrastructure for Character.AI's consumer-facing discovery surfaces (recommendation, ranking, search), including data pipelines, model training, and serving. Focus on shipping intelligent features end-to-end.