Principal Engineer, LLM Application Development

RentSpree•Seattle, WA

4d•Hybrid

About The Position

We are seeking an exceptional Principal Engineer to lead the development, deployment, and ongoing evolution of cutting-edge generative AI and large-language-model (LLM) powered applications. This role sits at the intersection of deep technical ownership and cross-organizational leadership — driving best practices, architectural vision, and production-grade execution as we integrate AI capabilities into core products. As our AI Principal Engineer, you will be a cultural and technical leader championing the next era of AI-powered feature development. You will shape how AI is adopted across the engineering organization, mentor engineers, and ensure the quality, reliability, and compliance of mission-critical LLM systems.

Requirements

10+ years of professional software engineering experience with a strong record of technical leadership
Expertise building and shipping LLM applications and workflows at scale.
Demonstrated experience designing agentic systems and/or orchestration loops that integrate multiple AI capabilities and external tools.
Proven ability to create evaluation frameworks that ensure safety, reliability, and compliance for LLM-based applications.
Experience shipping multiple releases of AI-powered products from prototype through production and iteration.
Strong engineering instincts and ability to influence architectural direction.
Excellent communication skills with the ability to collaborate across functions.

Nice To Haves

Experience with generative AI frameworks (e.g., LangChain, LlamaIndex, Vertex AI, Azure OpenAI, etc.).
Background in distributed systems, platform engineering, or developer tooling.
Track record of mentoring senior engineers and fostering a culture of technical excellence.
Experience leading adoption of new development paradigms across large engineering organizations.

Responsibilities

Architect, build, and scale complex AI/LLM-driven applications, including workflows, agentic loops, tool-augmented reasoning systems, and other advanced generative AI integrations.
Write high-quality, maintainable, and well-tested code that ships to production and evolves through iterative releases.
Define core AI architecture patterns, standards, and reusable frameworks to accelerate AI feature delivery across teams.
Continuously refine AI tooling and developer workflows for efficiency, quality, and reliability.
Establish and lead robust evaluation frameworks to assess model performance, guardrails, safety, fairness, and compliance.
Collaborate with cross-functional stakeholders (Security, Legal, Product, Data) to ensure AI features meet ethical, privacy, and regulatory requirements.
Serve as a role model and coach, uplifting engineering excellence and AI fluency across the organization.
Evangelize best practices for building, validating, and maintaining LLM-based systems.
Drive adoption of AI-first software development tools and processes within teams.
Partner with Product, Design, and Data Science to define high-impact AI use cases and deliver them with pragmatic execution.
Translate complex technical concepts into clear guidance for non-technical audiences.
Balance long-term architectural investments with short-term delivery needs.

Benefits

Equity Options: Share in the value we’re creating—your work makes a real impact.
Team-First Culture: Join a group of talented, supportive teammates who inspire each other to do their best work and celebrate every win.
Learning & Development: Ongoing support for your growth through resources, coaching, and career development opportunities.
Health Coverage: Comprehensive employee + dependent medical, dental, and vision insurance, as well as HSA/FSA options. Plus, enjoy additional health perks like access to Headspace Care+, gym membership discounts, and much more — because your well-being matters, inside and out.
Plan for your future: Life, disability, and Simple IRA retirement plan with company match to support your future.
Flexible Vacation Policy: We trust you to take the time you need to rest and recharge.
Holidays: Enjoy 12 holidays throughout the year, as a part of our commitment to honoring culture, history, and time to recharge.
Events: We make time to connect and celebrate through reimbursable weekly team lunches, game nights, events, and more, both in-person and remotely.
Recognition Programs: Team members can recognize their peers with Sprees, which are redeemable for gift cards and/or donations to an organization of your choice, or nominate a colleague for a S.P.R.E.E. Award to spotlight above-and-beyond contributions, which may be rewarded with a spot bonus. Our Work Anniversary Program also honors employee milestones with personalized tokens of appreciation!
Business Expense Allowance & Internet Reimbursement: Get the tools and support you need to do your best work.
Parental Leave & Fertility Support: Inclusive benefits to support you and your family, wherever you are in life.
Legal & tax benefits: We offer group legal benefits and tax support through RocketLawyer.
Seattle HQ: If you’ll be working from our Seattle office, you’ll receive a company-sponsored Orca card to cover the cost of public transportation to and from the office!