[Remote] Principal Machine Learning Engineer

Note: The job is a remote job and is open to candidates in USA. HubSpot is an all-in-one marketing, sales, and service software platform building foundational AI infrastructure for agentic product experiences. The Principal Machine Learning Engineer will shape infrastructure for agent runtimes, evaluation systems, quality signals, model optimization, fine-tuning, and model routing while setting technical direction for scaling AI agents across the company.

Responsibilities

• 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
• 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

Skills

• 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

Benefits

• On-target commission for employees in eligible roles
• Annual bonus targets under HubSpot’s bonus plan for eligible roles
• Some roles are eligible to participate in HubSpot’s equity plan to receive restricted stock units (RSUs)
• Some roles may also be eligible for overtime pay

Company Overview

Company H1B Sponsorship