Principal Applied AI / ML Engineer

About this role:

We are seeking a Principal AI / ML Engineer to be a company-level technical thought leader and practitioner to help shape the future of Data and AI at Faire. This is a rare opportunity to drive broad technical strategy across data, engineering, and product while remaining deeply hands-on with cutting-edge AI research and applications. This role reports directly to the CTO of Faire.

You will:

• Shape the AI vision – Partner with product, design, strategy & analytics, machine learning, and the broader engineering leadership to define how AI can deliver transformational value to Faire’s retailers and brands. Offer thought leadership to shape company-wide priorities, with particular focus on product strategy and key investment directions.
• Prototype and unblock – Build and lead deployment of AI systems (LLM fine-tuning, RLHF, agent frameworks, etc.) that demonstrate what’s possible and accelerate adoption across teams. Act as a “super IC” who can dive deep to remove technical barriers, enabling the engineering organization to move quickly with AI and accelerate both development and impact.
• Architect the AI-ready stack – Shape the design of Faire’s technical ecosystem — spanning event logging, data warehouses, feature stores, and model serving — to ensure our infrastructure is AI-ready, scalable, and optimized for rapid experimentation and the safe & reliable deployment of innovative AI-enabled features.

What you’ll do:

• Serve as a trusted partner to executives and senior leaders, informing long-term strategy and product direction for AI-enabled experiences.
• Prototype and deploy cutting-edge AI systems using LLMs, generative AI, and agentic frameworks — taking concepts from zero-to-one and helping teams productionize them.
• Define technical standards and evaluation frameworks for safety, reliability, and business impact of AI features.
• Partner with infrastructure and platform teams to evolve Faire’s data pipelines, ML serving stack, and developer tools for AI-driven velocity.
• Mentor engineers and scientists across the org, raising the technical bar through coaching, tooling, knowledge sharing, and design reviews.
• Evangelize AI best practices and foster a culture of innovation that balances bold experimentation with pragmatic delivery.

Who you are:

• 10+ years of experience training and deploying machine learning models at scale, conducting applied AI research, and productizing advanced AI/ML technologies for impact.
• Proven track record of delivering production-grade AI systems at scale and influencing product strategy. Great at operating at the intersection of tech and product.
• Deep expertise in LLMs and modern AI techniques: fine-tuning, RLHF, RAG, embeddings, and agent frameworks.
• Strong systems background: experience with large-scale data pipelines, ML feature stores, distributed training, and model serving infrastructure.
• Proficiency with PyTorch, TensorFlow, JAX, Triton, or other relevant AI development and production frameworks.
• Exceptional communication and influence skills — able to collaborate with executives and inspire technical and non-technical audiences alike.
• MS or PhD in Computer Science, Machine Learning, Statistics, Operations Research or related field (or equivalent experience).
• Bonus: Open-source contributions, peer-reviewed publications, or experience in two-sided marketplace ecosystems.