Principal Software Engineer - Breeze Assistant

POS-31592 About the Team Breeze Assistant is HubSpot’s AI-powered "System of Action." Our mission is to transform how marketers, sales representatives, and support professionals work by moving beyond simple chat interfaces to an autonomous, proactive assistant that executes GTM (Go-To-Market) workflows. Unlike traditional search-based AI, Breeze Assistant is deeply integrated into the HubSpot CRM. We build the intelligence and infrastructure that allow AI to not just answer questions, but to take actions—like preparing for a complex meeting, researching prospects across the web, and automating multi-step cross-functional tasks—all while maintaining the trust and brand voice of our customers. About the Role 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. Key Expectations 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. What You Bring 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. Pay & Benefits The cash compensation below includes base salary, on-target commission for employees in eligible roles, and annual bonus targets under HubSpot’s bonus plan for eligible roles. In addition to cash compensation, 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. Individual compensation packages are tailored to your skills, experience, qualifications, and other job-related reasons. This resource will help guide how we recommend thinking about the range you see. Learn more about HubSpot’s compensation philosophy. Benefits are also an important piece of your total compensation package. Explore the benefits and perks HubSpot offers to help employees grow better. At HubSpot, fair compensation practices aren’t just about checking off the box for legal compliance. It’s about living out our value of transparency with our employees, candidates, and community.Annual Cash Compensation Range:$313,800—$502,080 USD We know the confidence gap and impostor syndrome can get in the way of meeting spectacular candidates, so please don’t hesitate to apply — we’d love to hear from you. If you need accommodations or assistance due to a disability, please reach out to us using this form. At HubSpot, we value both flexibility and connection. Whether you’re a Remote employee or work from the Office, we want you to start your journey here by building strong connections with your team and peers. If you are joining our Engineering team, you will be required to attend a regional HubSpot office for in-person onboarding. If you join our broader Product team, you’ll also attend other in-person events, such as your Product Group Summit and other gatherings, to continue building on those connections. If you require an accommodation due to travel limitations or other reasons, please inform your recruiter during the hiring process. We are committed to supporting candidates who may need alternative arrangements Massachusetts Applicants: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Germany Applicants: (m/f/d) - link to HubSpot's Career Diversity page here. India Applicants: link to HubSpot India's equal opportunity policy here. About HubSpot HubSpot (NYSE: HUBS) is an AI-powered customer platform with all the software, integrations, and resources customers need to connect marketing, sales, and service. HubSpot's connected platform enables businesses to grow faster by focusing on what matters most: customers.  At HubSpot, bold is our baseline. Our employees around the globe move fast, stay customer-obsessed, and win together. Our culture is grounded in four commitments: Solve for the Customer, Be Bold, Learn Fast, Align, Adapt & Go!, and Deliver with HEART. These commitments shape how we work, lead, and grow. We’re building a company where people can do their best work. We focus on brilliant work, not badge swipes. By combining clarity, ownership, and trust, we create space for big thinking and meaningful progress. And we know that when our employees grow, our customers do too. Recognized globally for our award-winning culture by Comparably, Glassdoor, Fortune, and more, HubSpot is headquartered in Cambridge, MA, with employees and offices around the world. Explore more: HubSpot Careers Life at HubSpot on Instagram HubSpot may use AI to help screen or assess candidates, but all hiring decisions are always human. More information can be found here. 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