Jobs in Sunnyvale

At Carbon, our mission goes beyond 3D printing. We are enabling creators everywhere to make what the world needs, right now. Our company is built on the idea that diverse fields of study must come together to solve intractable problems. We have grand ambitions to create technology that will influence industry around the world. You will be joining a diverse team with a vibrant culture, where team success is as important as celebrating individual contributions. Help us change the world and we will help you change yours. Working at the intersection of hardware, software, and molecular science, Carbon is committed to delivering on the promise of 3D printing, enabling commercial customers to go beyond basic prototyping to produce products with real-world applications. With our cutting-edge technology, we are seeing customers innovate and manufacture parts with unmatched reliability, speed, and quality. You’ll be joining a close-knit team, working with experts in 3D geometry, web technologies, Linux, and everything in between. We’ve had fun team activities where we escape rooms (real and virtual), play games, and cook delicious food. We also have a variety of employee-started communities at Carbon: baking, bootcamp, yoga, gaming, book club, diversity groups, and many more that you can participate in and maybe even start your own! This role is based in our Sunnyvale, CA location and is onsite Mon - Friday. This role is not eligible for current Visa sponsorship. This role is not eligible for relocation. You will : Build High-Impact Web Applications : You will design and ship customer-facing web apps that integrate with our Tier-0 services (Fleet Management, Auth, and Core APIs), helping keep the foundational systems that power our global printer network resilient as we add new features on top. Create Modern APIs : Design and build the REST and gRPC interfaces that power our web applications and expose platform capabilities to other

About the Team The Ads & Promos Delivery team powers the last-mile delivery of ads and promotions, two marketing products offered to merchants, connecting merchant intent with consumer demand across search and discovery experiences. As a Principal Engineer, you will lead the technical direction for AI-first experiences, including ranking and relevance systems that sit at the core of our ads marketplace and shape how ads are selected, ordered, and personalized in real time across all verticals. You will design and build next-generation AI-first ranking systems using state-of-the-art techniques such as sequence modeling, deep learning, and large language models (LLMs). Your work will span query understanding, user and merchant representation learning, contextual relevance, and multi-objective optimization, balancing advertiser value, consumer experience, and marketplace health at scale. You will set the long-term technical vision, drive cross-team alignment, and translate cutting-edge research into production systems that operate under strict latency, scale, and reliability constraints. As DoorDash expands into 40+ global markets and new verticals such as Grocery and Retail, this role offers a rare opportunity to define how modern AI, including sequential models and LLM-powered decisioning, reshapes ads relevance in a closed-loop marketplace. About the Role Apply state-of-the-art machine learning and LLM techniques to problems across personalization, query understanding, user and content understanding. Rigorously evaluate ML and LLM models using a combination of offline analysis and online experimentation, designing metrics and experiments that clearly measure quality, impact, and tradeoffs. Own the full model lifecycle from research to production, including data analysis, model development, evaluation, offline and online A/B testing, and continuous iteration. Partner closely with product managers, data scientists, and designers to ensure AI-driven systems deliver