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Principal Engineer, LLM – Platform and Tooling
Location
United States
Posted
37 days ago
Salary
$238.4K - $330.2K / year
Seniority
Lead
Job Description
Principal Engineer, LLM – Platform and Tooling
Upstart
• Define and drive the multi-year technical roadmap for the Core GenAI Platform, influencing adoption and alignment across several engineering teams • Collaborate with CTO/VP-level and above leadership to influence business strategy with technical insight • Lead architecture and design of large-scale, mission-critical systems for model inference, orchestration, and compliance • Identify and solve systemic technical risks that impact the entire company and business-critical AI initiatives • Represent Upstart internally and externally as a thought leader in GenAI systems through executive reviews, cross-company forums, and industry venues • Establish operational standards for GenAI integrations, ensuring security, fairness, and reliability at scale • Build high-leverage, generalizable platform components that meaningfully accelerate the productivity of engineers across Upstart • Mentor senior engineers, other principal engineers, and shape the growth of future technical leaders, fostering a culture of learning and excellence
Job Requirements
- Bachelor’s degree in Computer Science, Engineering, or Mathematics, or a related field (or its equivalent) + 8 years of experience
- Deep expertise in LLM-specific infrastructure such as inference optimization (quantization, ONNX, streaming).
- Ability to design scalable RAG architectures and manage the lifecycle of models from experimentation to high-availability production environments including vector databases.
- Proven experience building robust, automated evaluation pipelines using both heuristic metrics and 'LLM-as-a-judge' frameworks to ensure model accuracy and safety.
- Hands-on experience with LLM toolchains such as LangChain, LlamaIndex, or OpenAI APIs
- Experience designing and operationalizing ML/LLM platforms at scale, including optimization for cost, latency, and reliability and the platform infrastructure needed to support them.
- Deep Expertise in best practices and risks for GenAI including hallucination mitigation, fairness, explainability, and data privacy
- 12+ years of experience and 5+ leading cross functional technical initiatives is preferred
- Proven ability to execute or guide model fine-tuning and alignment (RLHF/DPO) to optimize LLM performance for specialized consumer use cases and proprietary datasets is preferred.
- Full-stack engineering experience (Python, FastAPI, Kotlin, Spring, React/TypeScript, or similar) is preferred.
- Deep expertise in backend systems and infrastructure technologies such as Kubernetes, Docker, Terraform, and cloud-native architectures is preferred.
Benefits
- Competitive compensation, including base pay, bonus opportunities, and annual equity grants that vest quarterly
- Generous 401(k) plan with Upstart matching $2 for every $1 contributed, up to $15,000 per year
- Employee Stock Purchase Plan (ESPP) with discounted stock purchase options for eligible employees
- Affordable medical, dental, and vision coverage, with multiple plan options - Upstart covers 90% to 100% of the cost depending on the plans you choose
- Health Savings Account contributions from Upstart for eligible plans
- Income protection benefits, including company-paid Basic Life, AD&D, and Short- and Long-Term Disability coverage, with options to purchase supplemental coverage
- Paid time off, sick and safe time, and company holidays
- Paid family and parental leave to support caregiving and major life moments
- Family-centered benefits through Carrot and Cleo, supporting fertility, parenthood, and caregiving
- Employee Assistance Program (EAP) offering mental health support and life-centered resources
- Financial wellness resources, including access to financial planning tools and a financial concierge service
- Annual wellness allowance to support your physical and emotional well-being and personal development, based on what matters most to you
- Annual productivity allowance to invest in relevant tools and resources you need to do your best work, no matter where you work from
- Connection and community through team events and onsites, all-company updates, and employee resource groups (ERGs)
- Onsite perks, including catered lunches and fully stocked micro-kitchens when working from one of our four offices, located in the Bay Area, Austin, Columbus, and New York City (opening Summer 2026!).
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