HubSpot is building the foundational AI infrastructure that powers the next generation of agentic product experiences. In this onsite role in Cambridge, MA, you will help develop high-scope platform systems behind Breeze Engine (the platform behind Breeze Assistant and other AI-powered product experiences) and Aviator, HubSpot’s internal framework for building and running agents. You’ll focus on improving evaluation, quality, and scalability across the company through core ML and LLM infrastructure.
What you’ll build
- Infrastructure for agent runtime, evaluation, quality measurement, and model optimization.
- Tooling that helps teams see where their evals are strong, where coverage is missing, and where users are asking questions the system is not yet prepared to handle.
- Signal pipelines that surface user frustration, agent failure states, and quality issues before they show up as CSAT declines.
- A HubSpot-specific AI benchmark to evaluate model performance on real HubSpot workloads.
- Systems to evaluate new models across agents, improving product quality, reducing cost, and supporting future model routing.
- More repeatable fine-tuning and task-specific optimization for HubSpot’s AI use cases.
Who you are
- Deep experience with production ML, LLM, or AI infrastructure.
- Experience building systems at scale where reliability, latency, quality, and cost matter.
- A platform mindset, focused on systems rather than one-off solutions.
- Ability to work across infrastructure, product, backend, and ML teams.
- Experience with one or more areas such as eval frameworks, model serving, fine-tuning, signal extraction, experimentation, feedback loops, or model optimization.
- Energy for ambiguous, foundational problems where many answers still need to be invented.
- The ability to influence senior engineers and leaders through technical credibility and clear judgment.
Team context
This is a high-scope infrastructure role, not a feature-team position. The team owns Breeze Engine, the platform behind Breeze Assistant and other AI-powered product experiences, and Aviator, HubSpot’s internal framework for building and running agents.
Location and compensation
Cambridge, MA (onsite)
Salary: USD 285,800 to 457,300 per year
Flexibility and connection
HubSpot values both flexibility and connection. If you join the Engineering team as a Remote employee, you will be required to attend a regional HubSpot office for in-person onboarding. If you join the broader Product team, you will also attend other in-person events, such as your Product Group Summit and other gatherings.
If you require an accommodation due to travel limitations or other reasons, please inform your recruiter during the hiring process. HubSpot is committed to supporting candidates who may need alternative arrangements.
