Principal Software Engineer - Breeze Assistant

HubSpot

16d

About The Position

We are seeking a Principal Software Engineer to be the technical anchor for the Breeze Assistant product line. This role is for a builder who thrives at the intersection of robust distributed systems and bleeding-edge Generative AI. As a Principal Engineer, you are not just following a roadmap; you are helping define it by identifying what is possible with the latest LLM capabilities and turning those possibilities into production-grade features. You will balance the "need for speed" in AI experimentation with the "need for scale" required to support millions of users.

Requirements

User-First Mindset: You have a track record of building products that people love. You advocate for the end-user in design reviews and are willing to pivot technical strategies if it means a better outcome for the customer.
Proven Expertise in Distributed Systems: You have experience building and scaling high-throughput, low-latency systems with strict reliability requirements.
GenAI Proficiency: Deep experience with LLM orchestration, vector databases, and building production-grade RAG pipelines. You understand the trade-offs between different model architectures (GPT-4o, Claude, open-source models).
Agentic Thinking: A background in building autonomous or semi-autonomous systems where AI takes actions, handles tool-calling, and manages complex states.
A Bias for Action: You prefer a working prototype over a 20-page design doc. You have a habit of turning ambiguity into clear plans and working software.
Product Intuition: You care about the "why" behind the "what." You understand the pain points of sales and marketing professionals and build technology that solves them.

Responsibilities

Architectural Leadership for AI Actions: Define the patterns for how AI agents safely and predictably interact with HubSpot’s CRM and third-party ecosystems (Slack, Google Workspace, Microsoft 365).
Rapid GenAI Experimentation: Act as a "zero-to-one" builder. You stay current with the latest trends in LLMs, RAG (Retrieval-Augmented Generation), and Agentic frameworks (like LangGraph or AutoGen) to rapidly prototype and validate new "System of Action" capabilities.
Hands-on, High-Leverage Contributor: You ship production code. You will lead the development of high-impact initiatives, moving from a Jupyter notebook prototype to a petabyte-scale production system with ease.
System Reliability & Trust: Ensure that GenAI outputs are not just "cool," but trustworthy. You will drive the strategy around LLM evaluation, observability, and guardrails to ensure accuracy and data privacy.
Technical Mentorship & Multiplier: You will elevate the AI fluency of the entire engineering org. You’ll mentor senior engineers on prompt engineering, model selection, and the nuances of building non-deterministic systems.
Cross-Functional Influence: Partner with Product and AI Research teams to scope opportunities where GenAI can solve real-world GTM friction, ensuring our technical bets align with HubSpot’s broader AI strategy.
Rapid Domain Fluency: The AI landscape changes weekly. You must be able to dive into a new paper, model, or framework today and explain its strategic value to the team tomorrow.

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