Principal Software Engineer, Breeze

HubSpot

3d • $266,200 - $425,900 • Hybrid

About The Position

We are seeking a Principal Software Engineer to be the technical anchor for the Breeze Assistant platform. This role sits at the intersection of robust distributed systems, bleeding-edge Generative AI, and real customer outcomes. You will shape how Breeze moves from a highly capable assistant to a trusted, proactive agent: one that delivers durable, shareable artifacts grounded in CRM data; dynamically generates the UI a user needs for the task at hand; orchestrates multi-step workflows across HubSpot and third-party tools; and learns from every interaction to get better. The scale is real — millions of users, petabytes of context, and a platform that every HubSpot engineering team depends on.

Requirements

• Proven Expertise in Distributed Systems: You have built and scaled high-throughput, low-latency systems with strict reliability requirements — the kind that support high concurrency and vast data scale.
• GenAI Proficiency: Deep experience with LLM orchestration, vector databases, RAG pipelines, and multi-agent frameworks. You understand the trade-offs between model architectures, fine-tuning strategies, and inference costs, and you make principled bets.
• Agentic System Design: A background in building autonomous or semi-autonomous systems where AI takes actions, handles tool-calling, manages complex state, and recovers gracefully from failure. You've thought hard about the interplay between deterministic and non-deterministic steps in production workflows.
• Platform Thinking: You build for other builders. You design primitives — skills, tools, APIs, agentic harnesses — that internal teams and partners can compose into use cases you haven't imagined yet.
• User-First Mindset: You have a track record of building products that people love. You advocate for the end-user in design reviews and understand the pain points of sales and marketing professionals well enough to know when a technical tradeoff harms the outcome.
• Bias for Action: You prefer a working prototype over a lengthy design doc. You turn ambiguity into clear plans and working software, and you know how to balance the speed of AI experimentation with the rigor of production-grade systems.
• Rapid Domain Fluency: The AI landscape changes weekly. You dive into a new paper, model, or framework today and can explain its strategic value — and its limitations — to the team tomorrow.

Responsibilities

• Define the patterns for how AI agents safely interact with HubSpot's CRM, agentic primitives (skills, tools, memory, scheduled prompts), and third-party ecosystems (Slack, Google Workspace, Gong, etc.). You set the bar for how Breeze orchestrates deterministic and non-deterministic steps — choosing the right blend for trust, cost, and outcome quality.
• Extend the platform so every HubSpot team builds their highest-value deliverables into Breeze — expanding artifact types, opening the platform for internal builders, and driving toward Breeze being the default surface for customers and teams to build on.
• Work closely with the Context team to ensure every Breeze interaction is powered by complete, trustworthy growth context: company and industry data, outcome history, learning loops, and customer goals. You will build the technical bridges that let context evolve from a data layer into a dynamic, active collaborator in every user's GTM work.
• Act as a zero-to-one builder. You stay current with the latest in LLMs, RAG, and agentic frameworks to rapidly prototype and validate new capabilities — and you know when to ship the prototype and when to wait for production-grade infrastructure.
• Ship production code. You will lead development of high-impact initiatives, moving from a prototype to a production system supporting a broad user base.
• Ensure GenAI outputs are not just capable, but trustworthy. You will drive strategy around LLM evaluation, observability, guardrails, and data privacy — the technical foundation that lets customers trust Breeze enough to run real business processes on it.
• Partner with Product, AI Research, HubSpot engineering teams, and the Ecosystem teams to ensure every HubSpot team can expose their tools and API endpoints to Breeze — because coverage is the single biggest unlock for use-case completeness.
• Elevate AI fluency across the engineering org. Mentor senior engineers on prompt engineering, model selection, agentic design patterns, and the nuances of building non-deterministic systems at scale.

Benefits

• Cash compensation includes base salary, on-target commission for employees in eligible roles, and 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.
• Explore the benefits and perks HubSpot offers to help employees grow better.

What This Job Offers

• Job Type: Full-time
• Career Level: Principal
• Education Level: No Education Listed