Principal Machine Learning EngineerPosted today$457K

The opportunity

HubSpot is an all-in-one marketing, sales, and service software platform that helps businesses grow and succeed. With a user-friendly interface and powerful tools, HubSpot enables businesses to attract, engage, and delight customers, ultimately driving growth and increasing revenue.

What you'll do

  • Build infrastructure for agent runtime, evaluation, quality measurement, and model optimization.

  • Create tooling that helps teams understand where their evals are strong,: where coverage is missing, and where users are asking questions the system is not yet prepared to handle.

  • Design signal pipelines that surface user frustration, agent failure states,: and quality issues before they show up as CSAT drops.

  • Help define a HubSpot-specific AI benchmark for evaluating model performance on real HubSpot workloads.

  • Build systems to evaluate new models across agents, improving product: quality, reducing cost, and supporting future model routing.

  • Make fine-tuning and task-specific optimization more repeatable for HubSpot’s AI use cases.

What they're looking for

  • Has deep experience with production ML, LLM, or AI infrastructure.
  • Has built systems at scale where reliability, latency, quality, and cost matter.
  • Thinks in platforms, not one-off solutions.
  • Can work across infrastructure, product, backend, and ML teams.
  • Has experience with areas like eval frameworks, model serving, fine-tuning,: signal extraction, experimentation, feedback loops, or model optimization.
  • Is excited by ambiguous, foundational problems where many of the answers still need to be invented.
  • Can influence senior engineers and leaders through technical credibility and clear judgment.