Principal Research Engineer, Post-Training Location Redwood City, CA Employment Type Full time Department Technical Staff - ML Compensation $275K – $400K 🩺 Top-notch health coverage for you & your family, with majority of the premium covered 💰 We invest in your future with a generous 401(K) contribution 🍼 New parents, we've got you covered with incredible paid leave -up to 20 weeks 🌴 4 weeks of PTO to explore, unwind & come back recharged 🍽️ Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are ✨ Monthly wellness stipend to support you in your health journey Overview Application About the Role and Team As a Principal Research Engineer on the Post-Training team, you will drive the technical vision, execution, and evolution of the systems that transform foundation models into intelligent, engaging, and aligned products. Specifically, your team focuses on post-training of top-tier OSS LLMs (such as Mistral and Qwen) to power the highly immersive role-playing chat features of Character.AI. You will lead initiatives spanning data, algorithms, infrastructure, and evaluation, helping define how our models learn from feedback and improve over time. This is a highly cross-functional role that combines deep technical expertise with organizational leadership. You will partner closely with researchers, engineers, product teams, and infrastructure teams to identify the highest-leverage opportunities for improving model performance and user experience. Your work will directly shape the conversational experiences of millions of users every day. At Character.AI, you will have the opportunity to influence both the direction of our research and the systems that bring it into production, helping build the next generation of AI entertainment. What You'll Do Technical Leadership & Mentorship: Define and drive the technical roadmap for mid- and post-training systems, balancing research innovation with production reliability and scalability. You will mentor and grow a team of researchers and engineers through technical guidance, design reviews, and career development. Establish best practices for experimentation, model development, and deployment. Research & Model Development: Lead the development of alignment algorithms, optimization techniques, and training objectives to improve model capabilities and data efficiency. Drive advances in mid- and post-training methodologies including reinforcement learning, preference optimization, supervised fine-tuning, and emerging alignment approaches. Identify and execute high-impact research opportunities that improve model behavior, safety, and user engagement. Develop robust evaluation frameworks and quality signals to measure real-world model performance. Systems & Infrastructure: Lead the design of efficient training and inference systems for large-scale generative models. Architect scalable data pipelines that transform diverse data sources into high-quality training datasets. Partner with infrastructure teams to optimize distributed training, GPU utilization, and serving efficiency. Drive improvements in experimentation platforms, data quality systems, and model observability. Who You Are (Required Qualifications) PhD in Computer Science, Machine Learning, AI, or a related field, or equivalent industry experience. Significant experience leading technical projects or teams in machine learning, AI research, or large-scale distributed systems. Experience scaling and mentoring high-performing research and engineering teams. Deep understanding of modern machine learning techniques, including transformers, reinforcement learning, alignment methods, and large language models. Strong track record of delivering impactful research or applied ML systems in production environments. Expertise in designing, building, and maintaining production-quality ML systems and infrastructure. Experience training, serving, debugging, and optimizing large-scale models on GPU-based systems. Experience leading teams working on large language model training, mid-training, or post-training. Experience with product experimentation, online evaluation, and A/B testing frameworks. Strong software engineering skills with the ability to write clean, maintainable, and scalable code. Excellent communication skills and the ability to influence technical direction across teams. Lead complex, cross-functional initiatives across data, training infrastructure, evaluation, and model serving. Nice to Have Hands-on experience working directly with open-source models like Mistral and Qwen, particularly adapting them via mid- and post-training for specific personas, creative writing, or role-playing applications. Familiarity with cloud-native ML infrastructure, including Kubernetes, Docker, and modern orchestration platforms. Publications in leading machine learning conferences or demonstrated contributions to the broader AI community. 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. Apply for this Job Powered by Privacy PolicySecurityVulnerability Disclosure

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

217 days ago

Staff Data Scientist, Monetization

Character.AI · Redwood City, California, United States

Pay

$250k–300k

Setting

Hybrid

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About the Role:

Character.AI is building the future of open-ended interactions between people and intelligent agents. As our platform scales, so does the opportunity to build sustainable, user-aligned monetization through subscriptions, advertising, and virtual currency economies.

We are seeking a Staff Data Scientist to partner closely with product, engineering, and growth teams to scale and optimize Character.AI’s monetization systems. This role focuses on enabling teams to design, launch, and iterate on data-informed, user-centric monetization experiences, while shaping how we measure, experiment with, and grow revenue without compromising the creativity and openness that define Character.AI.

What you’ll do:

You will partner closely with product and engineering teams to drive data-informed monetization across subscriptions, advertising, and virtual currency economies. This role defines success metrics, leads experimentation, and translates complex behavioral and economic data into actionable insights, while building the data science foundations needed to support rapid product iteration and long-term growth.

Qualifications:

7+ years of experience as a Data Scientist working on consumer-facing products, ideally in chat, social, UGC, or entertainment platforms
Strong intuition for identifying the right questions and quickly driving to high-impact insights
Proven ability to turn analysis into product decisions and shipped outcomes
Comfortable working in fast-moving, experimental environments with incomplete data
Experience building or scaling data science practices, including experimentation, metrics, and analytics tooling

You will be a good fit if you have:

Direct experience supporting monetization systems, including:
- Subscriptions and pricing
- Advertising or ad marketplaces
- Virtual currencies, economies, or gamified monetization
Background in consumer B2C products and/or B2B marketplaces

About Character.AI

empowers people to connect, learn and tell stories through interactive entertainment. Over 20 million people visit 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.

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

264 days ago

Software Engineer, Applied ML (Discovery, Recommendation & Search)

Character.AI · Redwood City, California, United States

Pay

$200k–300k

Setting

Hybrid

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Software Engineer, Applied ML (Discovery, Recommendation & Search) Location Redwood City, CA Employment Type Full time Location Type Hybrid Department Technical Staff - Engineering Compensation $200K – $300K 🩺 Top-notch health coverage for you & your family, with majority of the premium covered 💰 We invest in your future with a generous 401(K) contribution 🍼 New parents, we've got you covered with incredible paid leave -up to 20 weeks 🌴 4 weeks of PTO to explore, unwind & come back recharged 🍽️ Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are ✨ Monthly wellness stipend to support you in your health journey Overview Application About the Role As a Software / ML Engineer you will work cross functionally with product, data science and data platform to identify, design and implement the applied ML models and infra, ranging from the model optimization, data pipeline to model training and serving infrastructure, on one of the fastest growing native AI consumer applications on the market today. You will work on implementation of our ML backend systems to power the discovery surfaces including recommendation, ranking and search, supporting new AI generated content formats on our product while working with the team to support optimizing our existing systems. Requirements: B.A.S. in Computer Science or equivalent experience. 5+ years of industry experience Experience building/consuming RESTful and gRPC based web-services Experience building and managing infrastructure in a cloud environment (GCP, AWS or Azure) Familiar with one of the popular ML Frameworks like Pytorch, Tensorflow Experience writing highly performant service in a modern typed language Experience configuring and maintaining CI/CD pipelines and automated testing Desired Experience: Experience with shipping intelligent features, end-to-end, and from idea to production Experience with understanding, designing or implementing a full pipeline from data ingestion to model training. Experience with production AI/ML systems and services including optimizing GPU/TPU deployments Experience working with vector databases or other feature storage You will be a good fit if you are proactive and have a “get things done” mindset. Given our current pace of growth and load on our systems, most people have had a significant impact during their first week at the company. 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. Apply for this Job Powered by Privacy PolicySecurityVulnerability Disclosure

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

340 days ago

Research Engineer, AI Safety & Alignment

Character.AI · Redwood City, California, United States

Pay

$225k–400k

Setting

Hybrid

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Research Engineer, AI Safety & Alignment Location Redwood City, CA Employment Type Full time Location Type Hybrid Department Technical Staff - ML Compensation $225K – $400K • Offers Equity 🩺 Top-notch health coverage for you & your family, with majority of the premium covered 💰 We invest in your future with a generous 401(K) contribution 🍼 New parents, we've got you covered with incredible paid leave -up to 20 weeks 🌴 4 weeks of PTO to explore, unwind & come back recharged 🍽️ Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are ✨ Monthly wellness stipend to support you in your health journey Overview Application About the role and team Joining us as a Research Engineer, you'll be at the forefront of tackling one of the most critical challenges in AI today: safety and alignment. Your work will be pivotal in understanding and mitigating the risks of advanced AI, conducting foundational research to make our models safer, and solving the core technical problems of AI alignment—ensuring our models behave in accordance with human values and intentions. The Safety team is dedicated to pioneering and implementing techniques that make our models more robust, honest, and harmless. As a Research Engineer, you will bridge the gap between theoretical research and practical application, writing high-quality code to test hypotheses and integrating successful safety solutions directly into our products. Your research will not only protect millions of users but also contribute to the broader scientific community's understanding of how to build safe, beneficial AI. What you'll do Develop and implement novel evaluation methodologies and metrics to assess the safety and alignment of large language models. Research and develop cutting-edge techniques for model alignment, value learning, and interpretability. Conduct adversarial testing to proactively uncover potential vulnerabilities and failure modes in our models. Analyze and mitigate biases, toxicity, and other harmful behaviors in large language models through techniques like reinforcement learning from human feedback (RLHF) and fine-tuning. Collaborate with engineering and product teams to translate safety research into practical, scalable solutions and best practices. Stay abreast of the latest advancements in AI safety research and contribute to the academic community through publications and presentations. Who you are Hold a PhD (or equivalent experience) in a relevant field such as Computer Science, Machine Learning, or a related discipline. 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, particularly transformers and reinforcement learning, with a focus on their safety implications. Are passionate about the responsible development of AI and dedicated to solving complex safety challenges. 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) Experience with explainable AI (XAI) and interpretability techniques. Have research in AI safety, alignment, ethics, or a related area. Knowledge of the broader societal and ethical implications of AI, including policy and governance. 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. Apply for this Job Powered by Privacy PolicySecurityVulnerability Disclosure

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

476 days ago

Software Engineer, Backend/Applied ML (Safety & Integrity)

Character.AI · Redwood City, California, United States

Pay

$150k–300k

Setting

Hybrid

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Software Engineer, Backend/Applied ML (Safety & Integrity) Location Redwood City, CA Employment Type Full time Location Type Hybrid Department Technical Staff - Engineering Compensation $150K – $300K • Offers Equity 🩺 Top-notch health coverage for you & your family, with majority of the premium covered 💰 We invest in your future with a generous 401(K) contribution 🍼 New parents, we've got you covered with incredible paid leave -up to 20 weeks 🌴 4 weeks of PTO to explore, unwind & come back recharged 🍽️ Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are ✨ Monthly wellness stipend to support you in your health journey Overview Application About the role We’re looking for a talented and creative Software Engineer to join our Safety Engineering team at Character.AI! In this role, you will be at the forefront of designing, developing, and scaling robust backend systems and leveraging applied machine learning to tackle critical integrity and safety challenges. You will be architecting and implementing innovative solutions in a key role in addressing the unique safety challenges that come with human-to-AI interaction—bringing your technical expertise to the table as we define industry best practices in this emerging space. This is a high-impact role where you will provide technical leadership, drive innovation, and contribute to the core of our platform's trustworthiness. What you'll do Architect & Build: Design, develop, and maintain highly scalable, resilient, and performant backend systems that power our integrity and safety features. Lead Complex Solutions: Lead the technical design and implementation of sophisticated backend solutions for detecting, preventing, and mitigating a wide array of integrity risks. This includes traditional issues (e.g., content classification, spam, etc.) as well as emerging threats related to Generative AI (e.g., misuse of generative models, generation of harmful or biased content, etc). Apply Machine Learning: Conceptualize, develop, deploy, and iterate on machine learning models and algorithms to address complex integrity challenges. This includes areas like content classification (including AI-generated content), anomaly detection, risk scoring, behavior analysis, and developing safeguards for Generative AI systems (e.g., robust content filtering, bias mitigation techniques, and output monitoring). Cross-Functional Collaboration: Work closely with product managers, data scientists, AI researchers, security teams, and operations to define requirements, design innovative solutions, and deliver impactful integrity systems, especially for Generative AI products. Technical Strategy & Roadmap: Drive the long-term technical vision and roadmap for backend integrity systems and applied ML capabilities, with a keen eye on addressing Generative AI safety concerns with an alignment with company objectives. Mentorship & Leadership: Provide technical guidance and mentorship to other engineers on the team and across the organization, fostering a culture of engineering excellence. Champion Best Practices: Advocate for and implement best practices in software engineering, distributed systems design, data engineering, and the full lifecycle of ML model development, including specific considerations for the safety and ethics of Generative AI. System Optimization: Continuously analyze and improve the performance, scalability, reliability, and cost-effectiveness of existing integrity platforms and ML models. Stay Current: Keep abreast of emerging threats, new technologies, and advancements in backend engineering, distributed systems, the application of machine learning to trust and safety, and the evolving landscape of Generative AI safety research and mitigation techniques. Who you are 8+ years of professional software engineering experience, with a strong emphasis on backend systems development. Bachelor's, Master's, or PhD degree in Computer Science, Engineering, or a related technical field. Proven track record of designing, building, and operating complex, large-scale, and highly available distributed systems. Expertise in one or more backend programming languages such as Python, Go, Java, or C++. Hands-on experience in applying machine learning techniques to solve real-world problems, specifically with demonstrable experience in addressing integrity, trust, or safety challenges. Solid understanding of the machine learning lifecycle, including data gathering and cleaning, feature engineering, model selection, training, validation, A/B testing, deployment, and operational monitoring. Exceptional problem-solving abilities, with a knack for tackling ambiguous and technically challenging problems. Proven ability to work in a fast-paced development environment and deliver timely results. Strong communication, interpersonal, and leadership skills, with the ability to articulate complex technical concepts to diverse audiences. You will be a great fit if: You care deeply about Trust & Safety and see it as a value-add to the business Prior experience in a dedicated Trust & Safety, Integrity, or Risk engineering team. Contributions to open-source projects or publications in relevant fields. Experience leading large, cross-cutting technical projects. 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. Apply for this Job Powered by Privacy PolicySecurityVulnerability Disclosure

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

530 days ago

Software Engineer, Backend

Character.AI · Redwood City, California, United States

Pay

$180k–300k

Setting

Hybrid

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Software Engineer, Backend Location Redwood City, CA Employment Type Full time Location Type Hybrid Department Technical Staff - Engineering Compensation $180K – $300K • Offers Equity 🩺 Top-notch health coverage for you & your family, with majority of the premium covered 💰 We invest in your future with a generous 401(K) contribution 🍼 New parents, we've got you covered with incredible paid leave -up to 20 weeks 🌴 4 weeks of PTO to explore, unwind & come back recharged 🍽️ Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are ✨ Monthly wellness stipend to support you in your health journey Overview Application About the Role We are looking for a talented and motivated Backend Engineer to join our team. You will be responsible for building and maintaining scalable, high-performance backend systems that power our products. Collaborating with designers, data scientists, and engineers, you'll play a key role in conceptualizing, designing, and delivering robust and efficient backend solutions. What you’ll do Design, develop, and maintain scalable backend services that support our applications and infrastructure. Implement secure and efficient APIs to support frontend applications and third-party integrations. Optimize system performance, reliability, and scalability through effective architecture and engineering best practices. Work closely with product managers, data analysts, and frontend engineers to develop backend solutions that align with business and user needs. Ensure high availability, fault tolerance, and performance of backend systems. Monitor system health, troubleshoot issues, and implement improvements to enhance efficiency and stability. Maintain security best practices to protect user data and system integrity. Stay up to date with industry trends and emerging technologies in backend development and distributed systems. Who you are 5+ years of experience in backend development, building scalable and reliable applications. Strong proficiency in programming languages such as Python, Java, or Go. Python and Go are preferred. Experience with database technologies such as PostgreSQL, MySQL, or NoSQL solutions. Familiarity with designing and integrating APIs, including REST and GraphQL. Understanding of distributed systems, microservices architecture, and cloud platforms (AWS, GCP, or Azure). Experience with containerization and orchestration tools like Docker and Kubernetes. Strong problem-solving skills and the ability to optimize system performance and reliability. Excellent communication skills and the ability to work effectively in a collaborative environment. Preferred Qualifications Experience with event-driven architectures and messaging systems (Kafka, RabbitMQ, etc.). Knowledge of caching strategies and performance optimization techniques. Experience working on large-scale, high-traffic applications. Familiarity with CI/CD pipelines and DevOps best practices. Exposure to machine learning or data-driven applications. 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. Apply for this Job Powered by Privacy PolicySecurityVulnerability Disclosure

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

574 days ago

Software Engineer, Monetization

Character.AI · Redwood City, California, United States

Pay

$150k–300k

Setting

Hybrid

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Software Engineer, Monetization Location Redwood City, CA Employment Type Full time Location Type Hybrid Department Technical Staff - Engineering Compensation $150K – $300K • Offers Equity 🩺 Top-notch health coverage for you & your family, with majority of the premium covered 💰 We invest in your future with a generous 401(K) contribution 🍼 New parents, we've got you covered with incredible paid leave -up to 20 weeks 🌴 4 weeks of PTO to explore, unwind & come back recharged 🍽️ Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are ✨ Monthly wellness stipend to support you in your health journey Overview Application About the Role We are scaling personalized AI to billions of users and monetization is at the core of making this vision sustainable. Our monetization team is reimagining how users interact with virtual currency, subscriptions, and premium features in ways that feel intuitive, rewarding, and fun. We’re looking for a product engineer who thrives at the intersection of core product, commerce, and user experience—someone excited to design and build systems that not only drive revenue but also enhance user delight. If you have experience with subscriptions, ads, virtual economies, or in-app purchase flows, and care deeply about building high-quality user experiences we’d love to work with you. What you’ll do Build and optimize user-facing features across mobile and web that power payments, subscriptions, and in-app purchase flows. Design and experiment with monetization surfaces, from virtual currency systems to premium upsells to advertising. Partner closely with design and product to create delightful, performant, and trustworthy purchase experiences. Collaborate with data science to define monetization success metrics, run experiments, and analyze outcomes. Work with backends to design scalable, reliable systems for payments, entitlements, and transactions. Maintain a high bar for UI/UX polish, performance, and privacy in sensitive user flows. Help shape the company’s approach to monetization experimentation, including frameworks for A/B testing and iteration velocity. Who you are Experience in consumer products with monetization, IAP, or subscription flows. Deep understanding of Typescript, React, React Native, Tailwind, HTML, and modern front-end best practices. Comfortable contributing to backend services, ideally with Python or Golang, especially for payments or commerce systems. Demonstrated experience shipping user-facing features that drove measurable monetization or engagement outcomes. Proven ability to thrive in a fast-paced environment, balancing iteration speed with quality and reliability. Excellent communication and collaboration skills across engineering, product, design, and data. Nice to Have Background in gaming, virtual currencies, or digital goods ecosystems. Prior experience with payment processors, subscription platforms, or marketplace ecosystems. Passion for user psychology, reward systems, and designing engaging monetization loops. Exposure to startup or zero-to-one product development environments. 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. Apply for this Job Powered by Privacy PolicySecurityVulnerability Disclosure

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

605 days ago

Software Engineer, Core Product

Character.AI · Redwood City, California, United States

Pay

$150k–300k

Setting

Hybrid

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Software Engineer, Core Product Location Redwood City, CA Employment Type Full time Location Type Hybrid Department Technical Staff - Engineering Compensation Estimated Salary $150K – $300K • Offers Equity 🩺 Top-notch health coverage for you & your family, with majority of the premium covered 💰 We invest in your future with a generous 401(K) contribution 🍼 New parents, we've got you covered with incredible paid leave -up to 20 weeks 🌴 4 weeks of PTO to explore, unwind & come back recharged 🍽️ Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are ✨ Monthly wellness stipend to support you in your health journey Overview Application About the role and team We are building the future of open-ended interactions between people and intelligent agents. This requires rethinking design, user interfaces, workflows and interactivity from first principles. We’re looking for a Core Product engineer who is genuinely excited about this future and can make significant contributions to our front-end development efforts. If you are a skilled software engineer with a deep passion for front end development, design, craft, and you thrive in a fast-paced, agile environment, we encourage you to apply for this exciting opportunity. What you’ll do Develop highly performant, visually appealing, and user-friendly interfaces that push the boundaries of what's possible. Enhance and refine our user interface, focusing on engaging our users by fulfilling their needs, desires, and expectations. Collaborate closely with the design team to translate visionary concepts into tangible user experiences and product interfaces. Establish, evolve, and maintain design foundations, systems, and patterns for the team, setting the bar for product consistency and quality. Collaborate with others to define and implement new product features and design patterns Who you are Experience as a Front-End or Full-Stack Software Engineer with a strong focus on user experience and design systems Deep understanding of Typescript, React, React Native, Tailwind, HTML, and modern front-end best practices. Demonstrated experience with building features and experiences for consumer products Passionate about the pixels, an exceptional eye for detail, and a focus on craft and polish Proven ability to work in a fast-paced development environment and deliver timely results. Excellent communication and collaboration skills across engineering, product, design, and data. 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. Apply for this Job Powered by Privacy PolicySecurityVulnerability Disclosure

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

958 days ago

Research Engineer, Post-Training (All Industry Levels)

Character.AI · United States

Pay

$225k–400k

Setting

Remote

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Research Engineer, Post-Training (All Industry Levels) Location Redwood City or New York City Employment Type Full time Location Type Hybrid Department Technical Staff - ML Compensation Estimated Base Salary $225K – $400K • Offers Equity 🩺 Top-notch health coverage for you & your family, with majority of the premium covered 💰 We invest in your future with a generous 401(K) contribution 🍼 New parents, we've got you covered with incredible paid leave -up to 20 weeks 🌴 4 weeks of PTO to explore, unwind & come back recharged 🍽️ Daily in-office catering plus a monthly Doordash stipend to help keep you fueled no matter where you are ✨ Monthly wellness stipend to support you in your health journey Overview Application 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. Apply for this Job Powered by Privacy PolicySecurityVulnerability Disclosure

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

1216 days ago

Machine Learning Infrastructure Engineer

Character.AI · Redwood City, California, United States

Pay

$150k–350k

Setting

Hybrid

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About the role

We’re looking for seasoned ML Infrastructure engineers with experience designing, building and maintaining training and serving infrastructure for ML research.

Responsibilities:

Provide infrastructure support to our ML research and product
Build tooling to diagnose cluster issues and hardware failures
Monitor deployments, manage experiments, and generally support our research
Maximize GPU allocation and utilization for both serving and training

Requirements:

4+ years of experience supporting the infrastructure within an ML environment
Experience in developing tools used to diagnose ML infrastructure problems and failures
Experience with cloud platforms (e.g., Compute Engine, Kubernetes, Cloud Storage)
Experience working with GPUs

Nice to have

Experience with large GPU clusters and high-performance computing/networking
Experience with supporting large language model training
Experience with ML frameworks like Pytorch/TensorFlow/JAX
Experience with GPU kernel development

About Character.AI

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!

Listed by Character.AI for a position based in the United States. Employers on this board attest they are hiring domestically.

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