Principal Research Engineer (AI)

Location: Palo Alto, California, United States

Salary: $400,000 – $550,000

Company

Inflection AI is a Public Benefit Corporation creating emotionally intelligent AI, including the personal AI agent Pi.

What you will do

• Own the model-improvement roadmap across capability, reliability, emotional intelligence, and enterprise readiness.
• Lead training and post-training strategies, including SFT, RLHF, DPO, GRPO, RLAIF, and reward modeling.
• Drive model architecture and optimization for transformer-based and hybrid architectures.
• Manage large-scale training efforts on distributed GPU clusters with 1,000+ GPUs.
• Execute data strategy covering curation, mixture design, synthetic data, and production feedback loops.
• Build evaluation and release-quality systems, including quality gates and regression detection.

Requirements

• Experience leading large-scale LLM, multimodal, or foundation-model training programs.
• Deep expertise with transformer-based models, hybrid architectures, and distributed training systems.
• Strong practical experience with alignment methods such as SFT, RLHF, DPO, and preference optimization.
• Experience operating GPU clusters at the scale of 1,000+ GPUs.
• PhD in Computer Science, ML, AI, or equivalent practical experience.
• Must be based in or be able to work in the Bay Area (Palo Alto, CA).

Culture & Benefits

• Comprehensive medical, dental, and vision insurance options.
• 401k matching program.
• Unlimited paid time off.
• Parental leave and flexibility for all parents and caregivers.
• Support for country-specific visa needs for international employees living in the Bay Area.