Data First Jobs

Harnham

Lead Machine Learning Engineer

Full Time · In Office · San Francisco, California (USA)

Posted Sep 8, 2026

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  • Title: Lead Machine Learning Engineer
  • Location: San Francisco (Hybrid)
  • Compensation: Up to $350,000 + Equity

We’re partnered with a well-funded early-stage startup rethinking how designers build in the AI era, backed by top-tier investors and operators from leading AI and technology companies. They’re building a next-generation design platform powered by LLMs, focused on helping product teams move from idea to production faster through intelligent, AI-driven workflows.

This is a foundational, high-ownership role where you’ll define and scale AI systems across the product. You’ll operate at the intersection of models, systems, and product, turning cutting-edge AI capabilities into reliable, measurable user-facing features.

  • What You’ll Do
  • Own AI architecture and technical direction across the product
  • Build and ship production-grade LLM features with clear quality and performance metrics
  • Design and optimize AI pipelines across prompting, retrieval, agents, and evaluation
  • Lead development of agentic systems and multi-step tool use workflows
  • Establish standards for model evaluation, benchmarking, and observability
  • Partner closely with product, design, and engineering to ship high-impact AI features
  • Requirements
  • 5+ years of software engineering experience
  • 2+ years working with LLM APIs and prompt engineering in production
  • Strong proficiency in TypeScript or Node.js and Python
  • Experience with LLM evaluation, benchmarking, and performance measurement
  • Hands-on experience with fine-tuning (LoRA, full fine-tuning, distillation)
  • Experience building agent-based AI systems
  • Ability to own systems end-to-end in a fast-paced environment
  • What You’ll Build
  • Fine-tuned models for design-to-code generation
  • Custom smaller models tailored to specific design workflows
  • Multi-step AI agent systems with tool use
  • Real-time, streaming AI experiences
  • Context-aware code generation and intelligent suggestions

If you're interested in building AI-native products that directly shape how modern teams design and build software, this is a rare chance to have early, meaningful impact on both the product and technical direction.

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Lead Machine Learning Engineer

Harnham

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