Alexa AI is looking for a Principal Applied Scientist to lead the science behind Alexa+, Amazon's LLM-powered conversational assistant. You will own the technical direction for key initiatives spanning large language model fine-tuning, alignment, agentic reasoning, and evaluation — directly shaping the experience for hundreds of millions of customers worldwide.

As a Principal Scientist, you are a hands-on technical leader. You define research directions, design and run rigorous experiments, and ensure that research translates into production systems at scale. You decompose ambiguous, hard problems into clear solutions. Your code, models, and documents are exemplary and frequently referenced across the organization.

You amplify your impact beyond your own work. You lead scientific reviews, scrutinize experimental design and modeling assumptions, and align teams toward coherent strategies. You mentor senior scientists, contribute significantly to hiring, and keep the broader scientific community current on state-of-the-art techniques. You bring business and industry context to technical decisions and can credibly present to executive leadership.

Key job responsibilities
Define and drive the science roadmap for conversational AI capabilities powered by large language models
Design, implement, and evaluate novel approaches to LLM fine-tuning, alignment (RLHF, DPO), and distillation for production deployment
Architect agentic systems — multi-step reasoning, tool use, planning, and orchestration — that work reliably at scale
Develop evaluation frameworks and methodologies that go beyond standard benchmarks to capture real-world conversational quality
Translate research advances into customer-facing products, working closely with engineering, product, and cross-functional science teams
Publish results at top-tier venues and represent Amazon in the broader research community
Mentor scientists at all levels and contribute to organizational planning, hiring, and technical culture

About the team
Alexa AI is building the science and technology behind Alexa+, Amazon's next-generation conversational assistant. Our team works at the intersection of large language models, reinforcement learning from human feedback and verifiable rewards, agentic architectures, and multilingual/multimodal understanding. We operate at massive scale — our models serve customers across dozens of languages and device types. If you want to push the frontier of conversational AI and see your work used by people every day, come join us.

Basic Qualifications

• 5+ years of hands-on work in predictive modeling and analysis experience
• PhD in Electrical Engineering, Computer Science, Mathematics, or a related technical field
• Experience working in predictive modeling and analysis
• Experience distilling informal customer requirements into problem definitions, dealing with ambiguity and competing objectives
• Experience programming in Java, C++, Python or related language
• Experience with leading experienced scientists as well as having a record of developing junior members from academia or industry to a career track in a business environment

Preferred Qualifications

• 10+ years of relevant work in industry or academia experience
• Knowledge of problem solving, algorithm design and complexity analysis
• Experience creating novel algorithms and advancing the state of the art
• Have peer-reviewed scientific contributions in premier journals and conferences

Amazon is an equal opportunity employer and does not discriminate on the basis of protected veteran status, disability, or other legally protected status.

Our inclusive culture empowers Amazonians to deliver the best results for our customers. If you have a disability and need a workplace accommodation or adjustment during the application and hiring process, including support for the interview or onboarding process, please visit https://amazon.jobs/content/en/how-we-hire/accommodations for more information. If the country/region you’re applying in isn’t listed, please contact your Recruiting Partner.

The base salary range for this position is listed below. Your Amazon package will include sign-on payments and restricted stock units (RSUs). Final compensation will be determined based on factors including experience, qualifications, and location. Amazon also offers comprehensive benefits including health insurance (medical, dental, vision, prescription, Basic Life & AD&D insurance and option for Supplemental life plans, EAP, Mental Health Support, Medical Advice Line, Flexible Spending Accounts, Adoption and Surrogacy Reimbursement coverage), 401(k) matching, paid time off, and parental leave. Learn more about our benefits at https://amazon.jobs/en/benefits.

USA, WA, Bellevue - 198,900.00 - 269,000.00 USD annually