Principal Software Engineer - Core GenAI Platform

Upstart is a leading AI lending marketplace focused on reducing the cost and complexity of borrowing for Americans. The Principal Software Engineer will provide technical leadership for the Core GenAI Platform, influencing architecture and adoption while mentoring engineers and ensuring the responsible use of AI across the organization.

Responsibilities:

• Define and drive the multi-year technical roadmap for the Core GenAI Platform, influencing adoption and alignment across several engineering teams
• Lead architecture and design of large-scale, mission-critical systems for model inference, orchestration, and compliance
• Identify and solve systemic technical risks that impact multiple teams and business-critical AI initiatives
• Build high-leverage, generalizable platform components that meaningfully accelerate the productivity of engineers across Upstart
• Mentor senior engineers (L5) and shape the growth of future technical leaders, fostering a culture of learning and excellence
• Collaborate with VP-level and above leadership to influence business strategy with technical insight
• 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

Requirements:

• Bachelor's degree in Computer Science, Engineering, or Mathematics, or a related field (or its equivalent) + 8 years of experience
• At least 3 years leading large-scale, cross-team technical initiatives
• Proven track record of delivering complex, distributed systems and platform infrastructure that span multiple teams
• Deep expertise in backend systems and infrastructure technologies such as Kubernetes, Docker, Terraform, and cloud-native architectures
• Experience designing and operationalizing ML/LLM platforms at scale, including optimization for cost, latency, and reliability
• Demonstrated ability to set long-term technical direction and influence organizational strategy
• Excellent communication skills with a history of driving alignment across engineering and business stakeholders
• Full-stack engineering experience (Python, FastAPI, Kotlin, Spring, React/TypeScript, or similar)
• Expertise in LLM-specific infrastructure such as inference optimization (quantization, ONNX, streaming), retrieval-augmented generation, and vector databases
• Hands-on experience with LLM toolchains such as LangChain, LlamaIndex, or OpenAI APIs
• Recognized as a technical leader beyond your immediate team, influencing platform strategy across organizations
• Awareness of industry best practices and risks in GenAI including hallucination mitigation, fairness, explainability, and data privacy
• Experience mentoring senior engineers and shaping organizational standards for operational excellence
• 10+ years of experience and 5+ leading cross functional technical initiatives