Applied AI Scientist - Small Language Models and AI Training

Overview: At Spellbrush, we are revolutionizing the gaming experience by crafting a 3D first-person adventure game where an AI companion plays a pivotal role. Imagine MiSide enhanced with language learning models, seamlessly integrated into gameplay rather than merely serving as a role-play chatbot.About UsAt Spellbrush, we are dedicated to creating exceptional anime games, and we proudly stand as a global leader in generative AI. Our flagship project is niji・journey.Our mission is straightforward: to use AI to animate characters and redefine narrative-driven gaming.What We’re CreatingWe have engineered an innovative in-house LLM storytelling system that merges AI, narrative, and gameplay, transcending the limitations of conventional chat-only encounters.This results in an AI companion that collaborates with players in solving puzzles, retains memories across different worlds, and alters the progression of each chapter.About The RoleJoin our elite team to redefine video game experiences. Collaborate with leading minds in the industry, including the creator of Warudo and Cytoid, as well as a Google DeepMind veteran behind Project Astra, and top-tier AI researchers.As an integral early member of this team, you will enjoy significant artistic and research autonomy in shaping what could be the next era of LLM-driven storytelling.

Overview: Join us at Spellbrush as we innovate in the world of gaming! We are developing an immersive 3D first-person adventure game where an AI companion drives the gameplay experience. Our goal is to create a game that integrates large language models (LLMs) in a way that enhances storytelling and player engagement, moving beyond simple chat interactions.About SpellbrushAt Spellbrush, we are dedicated to crafting exceptional anime games. As the leading generative AI studio, we are the creative force behind niji・journey. Our mission is clear: to harness AI in bringing vibrant characters to life and to redefine narrative-driven gaming experiences.Our ProjectWe have developed an innovative in-house LLM storytelling system that seamlessly integrates AI with narrative and gameplay, offering players a depth of interaction that transcends traditional gaming.Role OverviewAs an integral member of our small but highly skilled team, you will have the opportunity to shape the future of gaming. Collaborate with leading minds in the industry, including the creator of Warudo and a veteran from Google DeepMind behind Project Astra. Your role will afford you substantial creative and research freedom to pioneer LLM-driven storytelling.

Join Our Innovative TeamTavus is a forward-thinking research laboratory at the forefront of human-computer interaction. We are dedicated to creating AI Humans, a revolutionary interface that bridges the gap between individuals and machines, eliminating the friction commonly encountered in today's technology. Our advanced human simulation models empower machines to see, hear, respond, and even exhibit lifelike appearances, facilitating genuine, face-to-face interactions. By merging human emotional intelligence with machine efficiency, our AI Humans serve as reliable, empathetic agents available around the clock, in any language, tailored to user needs.Picture a therapist within reach for everyone, a personal trainer that fits seamlessly into your schedule, or a comprehensive team of medical assistants providing focused attention to every patient. With Tavus, individuals and organizations can develop AI Humans to foster connection, understanding, and responsiveness on a grand scale.As a Series A startup, we are backed by prestigious investors such as Sequoia Capital, Y Combinator, and Scale Venture Partners. Join us in crafting a future where humans and machines communicate effortlessly.Your RoleWe seek an AI Researcher to join our dynamic AI team and explore the frontiers of large language modeling within conversational AI. If you excel in fast-paced startup settings, enjoy experimenting with innovative ideas, and are eager to see your contributions realized in production, you will thrive here.Your Mission Conduct in-depth research on large language modeling and its adaptation for Conversational Avatars (e.g., Neural Avatars, Talking-Heads).Create methodologies to effectively model both verbal and non-verbal communication, dynamically adjusting avatar behaviors in real-time.Experiment with fine-tuning, adaptation, and conditioning techniques to enhance the expressiveness, control, and task specificity of LLMs.Collaborate with the Applied ML team to transition research from prototype to full-scale deployment.Stay informed on the latest advancements and contribute to defining the next breakthroughs.

Tavus – Multimodal AI Model OptimizationResearch EngineerAt Tavus, we are pioneering the human aspect of AI technology. Our objective is to make human-AI interactions as seamless and natural as in-person conversations, allowing for a human touch in areas that were once considered unscalable.We accomplish this through groundbreaking research in multimodal AI, focusing on human-to-human communication modeling (encompassing language, audio, and video) and the development of audio-visual avatar behaviors. Our innovative models drive applications ranging from text-to-video AI avatars to real-time conversational video experiences across sectors such as healthcare, recruitment, sales, and education.By empowering AI to perceive, listen, and engage with an authentic human-like presence, we are laying the groundwork for the next generation of AI workers, assistants, and companions.As a Series B company, we are supported by renowned investors, including Sequoia, Y Combinator, and Scale VC. Join us as we shape the future of human-AI interaction.The RoleWe are seeking an accomplished Research Scientist/Engineer with expertise in model optimization to be a vital part of our core AI team.The ideal candidate thrives in dynamic startup environments, is adept at setting priorities independently, and is open to making calculated decisions. We are moving swiftly and need individuals who can help navigate our path forward.Your MissionTransform state-of-the-art research models into fast, efficient, and production-ready systems through techniques such as sparsification, distillation, and quantization.Oversee the optimization lifecycle for critical models: establish metrics, conduct experiments, and evaluate trade-offs among latency, cost, and quality.Collaborate closely with researchers and engineers to convert innovative concepts into deployable solutions.RequirementsExtensive experience in deep learning with PyTorch.Practical experience in model optimization and compression, including knowledge distillation, pruning/sparsification, quantization, and mixed precision.Familiarity with efficient architectures such as low-rank adapters.Strong grasp of inference performance and GPU/accelerator fundamentals.Proficient in Python coding and adherence to best practices in research engineering.Experience with large models and datasets in cloud environments.Capability to read ML literature, reproduce results, and modify ideas accordingly.

Join Anthropic as a Senior Research Scientist on our Reward Models team, where you will spearhead groundbreaking research aimed at enhancing our understanding of human preferences at scale. Your innovative contributions will directly influence how our AI models, including Claude, align with human values and optimize for user needs. You will delve into the forefront of reward modeling for large language models, designing novel architectures and training methodologies for Reinforcement Learning from Human Feedback (RLHF). Your research will explore advanced evaluation techniques, including rubric-based grading, and tackle challenges such as reward hacking. Collaboration is key, as you'll work alongside teams in Finetuning, Alignment Science, and our broader research organization to ensure your findings result in tangible advancements in AI capabilities and safety. This role offers you an opportunity to address critical AI alignment challenges, leveraging cutting-edge models and substantial computational resources to further the science of safe and capable AI systems.

Join Achira in shaping the future of deep learning with cutting-edge generative, representational, and simulation models for molecules and materials. Our mission is to create foundational models that render the atomistic universe understandable, predictable, and designable.Why Choose Achira?Be part of an elite, cross-disciplinary team comprising ML researchers, physicists, chemists, and engineers who are redefining atomistic simulation through expansive foundation models.Advance the integration of deep learning with the principles of nature, merging generative AI, probabilistic reasoning, and molecular physics.Engage in projects at an unparalleled scale, tackling extensive datasets, computational challenges, and ambitious goals.Take full ownership of your research journey — from ideation and architecture to training, evaluation, and deployment.Flourish in a dynamic culture that values rigor, speed, creativity, and impact over bureaucracy.Position OverviewAs a Generative AI Researcher at Achira, you will contribute to the development of foundation simulation models — large-scale systems designed to learn the structure, dynamics, and energetics of the atomistic realm. These models will unite deep representation learning, generative modeling, and sophisticated simulation techniques.Your responsibilities will include:Crafting and training state-of-the-art deep generative models — including diffusion, autoregressive, flow-based, and latent-variable architectures focused on molecules, materials, and atomic systems.Creating expressive representations of molecular and atomistic structures and dynamics utilizing equivariant graph neural networks, geometric transformers, and latent encoders that respect physical symmetries and constraints.Innovating advanced sampling and simulation techniques that blend probabilistic inference, deep learning, and reinforcement learning to facilitate efficient exploration and simulation of learned energy landscapes.Developing models that comprehend, generate, and simulate the physical world, merging reasoning, simulation, and predictive capabilities.Working collaboratively with physicists and chemists to validate models against ab initio, molecular dynamics, and experimental datasets.Rapidly prototyping, benchmarking, and iterating — converting research concepts into reusable, scalable model components across Achira’s foundation model suite.

About Scale AI At Scale AI, we are committed to propelling the advancement of AI technologies. For over eight years, we have been a pioneer in the AI data sector, supporting groundbreaking innovations in areas such as generative AI, defense solutions, and autonomous driving. Following our recent Series F funding round, we are enhancing access to premium data to accelerate the journey towards Artificial General Intelligence (AGI). Building on our legacy of model evaluation for both enterprise and governmental clients, we are expanding our capabilities to establish new benchmarks for evaluations in both public and private domains. About This Role This position is at the leading edge of AI research and practical implementation, concentrating on reasoning within large language models (LLMs). The successful candidate will investigate critical data types vital for evolving LLM-based agents, including browser and software engineering agents. You will significantly influence Scale’s data strategy by pinpointing optimal data sources and methodologies to enhance LLM reasoning. To excel in this role, you will require a profound understanding of LLMs, planning algorithms, and fresh approaches to agentic reasoning, alongside inventive solutions to challenges in data generation, model interaction, and evaluation. Your contributions will lead to transformative research on language model reasoning, facilitate collaboration with external researchers, and engage closely with engineering teams to translate cutting-edge advancements into scalable, real-world applications.

Zyphra is an innovative leader in artificial intelligence, located in the heart of San Francisco, California.Role Overview:As a Research Engineer specializing in Language Model Pre-Training, you will play a pivotal role in defining our language model strategy through comprehensive pretraining development. Your close collaboration with our pretraining team will ensure that your insights contribute to the advancement of our next-generation models.Key Responsibilities:Conduct large-scale training runs and implement model parallelization techniques.Optimize the performance of our pretraining stack.Oversee dataset collection, processing, and evaluation.Research architecture and methodologies, including optimizer ablations.Qualifications:Demonstrated engineering prowess in developing reliable and robust systems.A quick learner with a passion for implementing innovative ideas.Exceptional communication and collaboration skills, capable of working effectively on both research and engineering implementations at scale.Preferred Skills:Profound expertise in addressing machine learning challenges and training models.Experience training on large-scale (multi-node) GPU clusters.In-depth understanding of model training pipelines, including model/data parallelism and distributed optimizers.Strong methodology for conducting rigorous ablations and hypothesis testing.Familiarity with large-scale, high-performance data processing pipelines.High proficiency in PyTorch and Python programming.Ability to navigate and understand extensive pre-existing codebases swiftly.Published research in machine learning in reputable venues is an advantage.Postgraduate degree in a relevant scientific field (Computer Science, Electrical Engineering, Mathematics, Physics).Why Join Zyphra?We value a research methodology that emphasizes thoughtful, methodical progress towards ambitious objectives. Both deep research and engineering excellence are given equal importance.Join us in an environment that fosters innovation, collaboration, and professional growth.

Join latentlabs, a pioneering company at the forefront of biotechnology, as we seek a talented Machine Learning Researcher specializing in generative modeling. You will become part of a dynamic, interdisciplinary team comprising machine learning experts, protein engineers, and biologists, all committed to revolutionizing biological control and disease treatment. In this role, you will design innovative generative models aimed at creating new proteins that exhibit functionality in wet lab assays.

About Sygaldry TechnologiesSygaldry Technologies is at the forefront of innovation, developing quantum-accelerated AI servers designed to significantly enhance the speed of AI training and inference. By merging quantum computing with AI, we are navigating the challenges of increasing compute costs and energy constraints, paving the way towards superintelligence. Our AI servers leverage a diverse range of qubit types in a fault-tolerant architecture, achieving the necessary balance of cost, scalability, and speed for advanced AI applications. We are committed to pioneering new frontiers in physics, engineering, and AI, tackling the most complex challenges with a culture grounded in optimism and rigor. We seek individuals passionate about defining the convergence of quantum and AI and making a meaningful global impact.About the RoleGenerative AI is revolutionizing computational possibilities but reveals the limitations of classical hardware. While diffusion models yield remarkable outcomes, their iterative sampling and high-dimensional score estimation often lead to computational inefficiencies.We are convinced that quantum computing holds the key to overcoming these challenges. As an ML Research Scientist, you will operate at the intersection of generative modeling and quantum acceleration, formulating theoretical foundations and practical applications that merge these domains. Your focus will be on identifying areas where quantum methods can deliver substantial advantages in generative workflows, providing not just incremental enhancements but transformative improvements grounded in mathematical principles.Your ResponsibilitiesGenerative Model Architecture & EfficiencyInnovate state-of-the-art diffusion and score-based generative models.Investigate computational bottlenecks in sampling, denoising, and likelihood estimation.Design and evaluate novel solver techniques for diffusion ODEs/SDEs.Quantum-Classical IntegrationDiscover mathematical structures in generative models that are suitable for quantum acceleration.Prototype hybrid workflows that utilize quantum subroutines to enhance classical processes.Conduct rigorous benchmarks comparing theoretical advantages against practical benefits in realistic scenarios.Research to ProductionTransform research findings into scalable implementations.Collaborate with quantum hardware teams to guide architectural specifications.Facilitate the integration of research insights into production environments.

About TavusTavus is at the forefront of innovation in human computing. Our mission is to develop AI Humans: an advanced interface that bridges the gap between individuals and machines, eliminating the friction found in current technologies. Our state-of-the-art human simulation models empower machines to see, hear, respond, and even exhibit realistic appearances—facilitating genuine, face-to-face interactions. AI Humans integrate the emotional insight of humans with the scalability and dependability of machines, making them reliable agents accessible 24/7, in any language, on our terms.Imagine having access to an affordable therapist, a personal trainer that fits your schedule, or a team of medical assistants dedicated to providing personalized care for every patient. With Tavus, individuals, enterprises, and developers have the tools to create AI Humans that connect, comprehend, and act with empathy on a large scale.We are a Series A company supported by esteemed investors such as Sequoia Capital, Y Combinator, and Scale Venture Partners.Join us in shaping a future where machines and humans genuinely understand one another.The PositionWe are seeking an AI Researcher to join our core AI team and advance the frontiers of multimodal conversational intelligence. If you excel in dynamic environments, enjoy transforming abstract concepts into functional code, and derive motivation from pushing the boundaries of possibility, this role is designed for you.Your Responsibilities Engage in research focusing on Foundational Multimodal Models specifically in the realm of Conversational Avatars (such as Neural Avatars and Talking-Heads).Develop models for video, audio, and language sequences utilizing Autoregressive and Predictive Architectures (e.g., V-JEPA) and/or Diffusion methodologies, with a focus on temporal and sequential data rather than static images.Collaborate closely with the Applied ML team to implement your research into production systems.Remain at the forefront of multimodal learning and assist us in defining what “cutting edge” will mean in the future.Ideal Candidate ProfilePhD (or nearing completion) in a relevant field, or equivalent practical research experience.Experience in multimodal machine learning, particularly focused on conversational interfaces.

About This Role Join Scale AI's Applied ML team as a Machine Learning Research Engineer, focusing on the development of advanced data infrastructure for leading agentic large language models (LLMs) such as ChatGPT, Gemini, and Llama. You will be responsible for architecting scalable multi-agent systems aimed at validating agentic reasoning and behaviors, enhancing human expertise, and conducting research to address real-world agent reliability failures, even in the face of strong benchmarks. Your contributions will directly impact the deployment of production fixes. This role is ideal for exceptional engineers who possess a deep research rigor and a strong commitment to creating practical, high-impact systems. You will iterate rapidly using data, leverage AI tools for accelerated development, and collaborate closely with engineering, product, and research teams. If you have a knack for transforming cutting-edge agent research into dependable deployed systems, we would love to hear from you.

About Retell AI Retell AI develops advanced voice AI technology for call centers, using first-principles approaches to create intelligent voice agents. These agents help businesses manage sales, support, and logistics communications while reducing reliance on large human teams. The company has reached $36M ARR in just 18 months, backed by Y Combinator and Alt Capital. With a team of 20, Retell AI is building a comprehensive customer experience platform, aiming for AI-powered contact centers by 2026. The vision: intelligent agents that execute, monitor, and improve customer interactions with minimal human oversight. Named a top 50 AI app by a16z: https://tinyurl.com/5853dt2x Ranked #4 on Brex's Fast-Growing Software Vendors of 2025: https://www.brex.com/journal/brex-benchmark-december-2025 Featured among top startups: https://leanaileaderboard.com/ Role Overview: Research Scientist - Voice AI Innovation This role centers on advancing machine learning for human-like voice agents in real-world settings. The Research Scientist will explore new methods in large language models (LLMs) and audio models, design evaluation techniques, and prototype systems that improve reasoning, reduce latency, and enhance conversational quality. The work involves open-ended ML challenges, rapid experimentation, and direct influence on the performance and cognitive abilities of voice AI systems at scale. Location San Francisco Bay Area

About World Labs: At World Labs, we create foundational world models capable of perceiving, generating, reasoning, and interacting with the 3D environment. Our mission is to unlock the full potential of AI through spatial intelligence, transforming perception into action, reasoning into insight, and imagination into creation. We believe that spatial intelligence will revolutionize storytelling, creativity, design, simulation, and immersive experiences across both virtual and physical realms. Our world-class team is driven by curiosity and passion, boasting diverse backgrounds in technology, from AI research and systems engineering to product design. This synergy fosters a tight feedback loop between our cutting-edge research and user-empowering products. Role Overview We are seeking an innovative Research Scientist specializing in generative modeling, especially diffusion models, to join our modeling team. This position is ideal for individuals with extensive expertise in applying diffusion models to images, videos, or 3D assets and scenes. While not mandatory, experience in any of the following areas will be considered a significant advantage: Large-scale model trainingResearch in 3D computer vision In this role, you will work closely with researchers, engineers, and product teams to translate advanced 3D modeling and machine learning techniques into practical applications, ensuring our technology stays at the forefront of visual innovation. This position entails substantial hands-on research and engineering work, taking projects from conception to production deployment. Key Responsibilities Design, implement, and train large-scale diffusion models for generating 3D worlds. Develop and experiment with large-scale diffusion models to introduce novel control signals, align with target aesthetic preferences, or optimize for efficient inference. Collaborate closely with research and product teams to comprehend and translate product requirements into actionable technical roadmaps. Contribute actively to all phases of model development, including data curation, experimentation, evaluation, and deployment. Continuously investigate and integrate the latest research in diffusion and generative AI. Serve as a key technical resource within the team, mentoring peers and promoting best practices in generative modeling and machine learning engineering.

Join Perplexity as a Research Engineering Manager, where you will spearhead a team of exceptional AI researchers and engineers dedicated to crafting the advanced models that power our innovative products. Our talented team has pioneered some of the most sophisticated models in agentic research, query understanding, and other critical domains that demand precision and depth. As we broaden our user base and expand our product offerings, our proprietary models are increasingly essential for delivering a premium experience to the world's most discerning users.You will explore our extensive datasets of conversational and agentic queries, applying state-of-the-art training methodologies to enhance AI model performance. Through proactive technical and organizational leadership, you will empower your team to create cutting-edge models for the applications that are most significant to our business and our users.

Join Cartesia as a Model Architecture ResearcherAt Cartesia, our vision is to revolutionize AI by creating interactive intelligence that is seamlessly integrated into your daily life. Unlike current models, our goal is to develop systems capable of processing extensive streams of audio, video, and text—1 billion text tokens, 10 billion audio tokens, and 1 trillion video tokens—directly on devices.As pioneers in innovative model architectures, our founding team, which originated from the Stanford AI Lab, has developed State Space Models (SSMs)—a groundbreaking foundation for training efficient, large-scale models. Our diverse team merges deep expertise in model innovation with a design-focused engineering approach, allowing us to create and deploy state-of-the-art models and applications.Backed by leading investors such as Index Ventures, Lightspeed Venture Partners, and many others, including industry veterans and advisors, we are poised to shape the future of AI.Your ContributionIn this role, you will drive forward-thinking research in neural network architecture, focusing on alternative models like state space models, efficient transformers, and hybrid architectures.Create innovative architectures that enhance model performance, inference speed, and adaptability in various environments, from cloud infrastructures to on-device implementations.Develop advanced capabilities for models, including statefulness, long-range memory, and novel conditioning mechanisms to boost expressiveness and generalization.Analyze architectural decisions and their effects on model characteristics such as scalability, robustness, latency, and energy consumption.Create frameworks and tools to assess architectural advancements, benchmarking their performance in both research and production contexts.Collaborate with interdisciplinary teams to translate architectural insights into scalable systems that deliver real-world impact.Your QualificationsExtensive experience in architecture design with a focus on advanced models such as state space models, transformers, and RNN/CNN variants.In-depth understanding of the interplay between architectural designs and system constraints, particularly in cloud and on-device deployments.Strong proficiency in the design and evaluation of neural network architectures.

Zyphra is an innovative artificial intelligence company located in the heart of San Francisco, California.The Opportunity:Join our dynamic team as a Research Engineer - Audio & Speech Models, where you will play a pivotal role in advancing Zyphra’s Audio Team. You will be instrumental in developing cutting-edge open-source text-to-speech and audio models. Your contributions will span the full spectrum of the model training process, from data collection and processing to the design of innovative architectures and training approaches.Your Responsibilities:Conduct large-scale audio training operationsOptimize the performance of our training infrastructureCollect, process, and evaluate audio datasetsImplement architectural and methodological improvements through rigorous testingWhat We Seek:A strong research mindset with the ability to navigate projects from ideation to implementation and documentation.Proficiency in rapid prototyping and implementation, allowing for swift experimentation.Effective collaboration skills in a fast-paced research environment.A quick learner who is eager to embrace and implement new concepts.Excellent communication abilities, enabling you to contribute to both research and engineering tasks at scale.Preferred Qualifications:Expertise in training audio models, such as text-to-speech, ASR, speech-to-speech, or emotion recognition.Experience with training audio autoencoders.Solid understanding of signal processing, particularly in audio.Familiarity with diffusion models, consistency models, or GANs.Experience with large-scale (multi-node) GPU training environments.Strong understanding of experimental methodologies for conducting rigorous tests and ablations.Interest in large-scale, parallel data processing pipelines.Competence in PyTorch and Python programming.Experience contributing to large, established codebases with rapid adaptation.

Zyphra is a cutting-edge artificial intelligence firm headquartered in the vibrant city of San Francisco, California.Position Overview:As a Research Scientist specializing in Model Architectures, you will play a pivotal role in Zyphra’s AI Architecture Research Team. Your responsibilities will include the design and thorough evaluation of innovative model architectures and training methodologies aimed at enhancing essential modeling capabilities (e.g., loss per flop or loss per parameter) and tackling core limitations inherent in current models. You will collaborate closely with our pre-training team to ensure that your findings are seamlessly integrated into our next-generation models.Qualifications:A strong research acumen and intuition.Proven ability to navigate research projects from initial conception to execution and final write-up.Exceptional implementation and prototyping skills, with the capability to swiftly transform ideas into experimental outcomes.A collaborative spirit and the ability to thrive in a fast-paced research environment.A deep curiosity and enthusiasm for understanding intelligence.Requirements:Experience with long-term memory, RAG/retrieval systems, dynamic/adaptive computation, and alternative credit assignment strategies.Knowledge of reinforcement learning, control theory, and signal processing techniques.A passion for exploring and critically evaluating unconventional ideas, with the ability to maintain a unique perspective.Familiarity with modern training pipelines and the hardware necessities for designing efficient architectures compatible with GPU hardware.Strong understanding of experimental methodologies for conducting rigorous ablations and hypothesis testing.High proficiency in PyTorch and Python programming.Ability to quickly assimilate into large pre-existing codebases and contribute effectively.Prior publication of machine learning research in reputable venues.Postgraduate degree in a scientific discipline (e.g., Computer Science, Electrical Engineering, Mathematics, Physics).Why Join Zyphra?We emphasize a structured research methodology that systematically addresses ambitious challenges in AI.

Anthropic is looking for a Research Engineer focused on model evaluations. This position involves research and development to assess and strengthen the performance of AI models. Teams are based in San Francisco and New York City, and the role supports remote work with required travel. Key responsibilities Design and implement evaluations for Anthropic's AI models Collaborate with team members to enhance model performance Contribute to research that pushes the boundaries of AI systems Location Remote-friendly (travel required) San Francisco, CA New York City, NY