Principal Applied Scientist- Agentic RL , Kiro

Amazon is hiring a Principal Applied Scientist- Agentic RL , Kiro in Santa Clara, United States. It pays $229k-$309k a year and Level rates it ; you can apply on Amazon.

Level's read on this job

Builds AI ●●●● is how Level rates this applied scientist role: the job is building AI systems.
The listed pay starts 37% above the typical applied scientist posting on Level.
Tools and skills the posting cites include Python, C and reinforcement learning.
Level classifies it as a lead role.
Level lists 20,000+ other open roles at Amazon.

AI in this role

Lead research and development of agentic reinforcement learning algorithms and training recipes for AI coding tools.

PythonC

reinforcement-learningmachine-learningllmscode-generationresearch

AWS Agentic AI is looking for a Principal Applied Scientist who will partner with world-class scientists and engineers to pioneer the next generation of AI-driven development tools. Join the Amazon Kiro LLM-Training team and help create the most efficient coding agents for Kiro that are transforming the software development landscape.

Key job responsibilities
As a key member of our team, you'll be at the forefront of innovation in agentic RL space:
- Push the boundaries of reinforcement learning and post-training methodologies for large language models specialized in code intelligence
- Invent and implement state-of-the-art agentic RL training recipes that operate at unprecedented Amazon scale
- Deploy revolutionary products that directly impact the daily workflows of millions of developers worldwide
- Break new ground in AI and machine learning, challenging what's possible in intelligent code assistance
- Publish and present your pioneering work at premier ML conferences (NeurIPS, ICML, ICLR )
- Accelerate innovation by working directly with customers to rapidly transition research breakthroughs into production systems

About the team
Kiro team is reimagining the builder experience through generative AI and foundation models. We're leveraging the latest advances in AI to transform how engineers work from IDE environments to web-based tools and services, empowering developers to tackle projects of any scale with unprecedented efficiency.

Basic qualifications

- PhD, or Master's degree and 10+ years of CS, CE, ML or related field experience
- 5+ years of hands-on large scale training experience
- Experience in patents or publications at top-tier peer-reviewed conferences or journals
- Experience programming in C++, Python or related language

Preferred qualifications

- Prior experience at training or inference large scale models

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

Los Angeles County applicants: Job duties for this position include: work safely and cooperatively with other employees, supervisors, and staff; adhere to standards of excellence despite stressful conditions; communicate effectively and respectfully with employees, supervisors, and staff to ensure exceptional customer service; and follow all federal, state, and local laws and Company policies. Criminal history may have a direct, adverse, and negative relationship with some of the material job duties of this position. These include the duties and responsibilities listed above, as well as the abilities to adhere to company policies, exercise sound judgment, effectively manage stress and work safely and respectfully with others, exhibit trustworthiness and professionalism, and safeguard business operations and the Company’s reputation. Pursuant to the Los Angeles County Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.

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, CA, Santa Clara - 228,700.00 - 309,400.00 USD annually
USA, NY, New York - 218,800.00 - 295,900.00 USD annually
USA, WA, Seattle - 198,900.00 - 269,000.00 USD annually

How we rate this

Principal Applied Scientist- Agentic RL , Kiro at Amazon rates 95 out of 100 for how much of the daily work is AI. That makes it Builds AI (AI Level 4 of 4). The level is about AI in the job, not seniority.

Classification

Builds AI. The job is building AI systems.

●●●● Builds AI80 to 100
●●●○ Works on AI60 to 79
●●○○ Uses AI40 to 59
●○○○ Little AI0 to 39

Levels come from how often the tools, models and workflows of the role are named in the posting itself. Read the description and count the AI tools, models and workflows it names.

Key facts

Principal Applied Scientist- Agentic RL , Kiro is an open job at Amazon.
Level rates this role AI Level 4 of 4: Builds AI.
The listed salary is $229k-$309k a year.
The role is based in US, CA, Santa Clara.
The job was posted on August 18, 2026.
Seniority: lead.
Applications are handled by Amazon. Apply on Amazon

Prepare for this job

Built from this posting and from similar jobs on Level.

Skills and AI tools this role asks for

Reinforcement learningMachine learningLLMsCode GenerationResearchPythonC

Also common in applied scientist jobs at this level

Java Deep learning NLP TensorFlow Spark Computer vision

Pay

This job starts at: $229k
Typical applied scientist job: $167k

This posting starts 37% above the typical applied scientist job. See applied scientist jobs

Questions you could be asked

Tell me about a project where reinforcement learning was part of your work. What did you do?
Tell me about a project where machine learning was part of your work. What did you do?
Tell me about a project where llms was part of your work. What did you do?
Tell me about a project where code generation was part of your work. What did you do?
Tell me about a project where research was part of your work. What did you do?

Adapt your resume

List these exact terms on your resume: Reinforcement learning, Machine learning, LLMs, Code Generation, and Research. An applicant tracking system matches the wording, not the idea.
Attach one line of real, concrete experience to at least one of them. A tool named with nothing behind it rarely survives a human read.
Lead with what you built, trained or shipped. This role is judged on the AI system itself, not the tools around it.

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