Sr Staff Frontend Engineer, Builder Enablement

About Gusto At Gusto, we're on a mission to grow the small business economy. We handle the hard stuff — payroll, health insurance, 401(k)s, and HR — so owners can focus on their craft and their customers. With teams in Denver, San Francisco, and New York, we support more than 400,000 small businesses nationwide and are building a workplace that reflects the people we serve. All full-time employees receive competitive base pay, benefits, and equity (RSUs) — because everyone who helps build Gusto should share in its success. Offer amounts are determined by role, level, and location. Learn more about our Total Rewards philosophy. AI is a fundamental part of how work gets done at Gusto. We expect all team members to actively engage with AI tools relevant to their role and grow their fluency as the technology evolves. AI experience requirements vary by role and will be assessed during the interview process. About the Role: As a Sr Staff Engineer on the Builder Enablement team, you will be instrumental in defining how every builder (engineer, designer, and beyond) at Gusto ships high-quality products with AI assistance. You'll help lead the development of AI tooling that teaches people and LLMs to use our design system correctly and drive experiments that improve AI-assisted builder workflows. If you're passionate about building tools that multiply the impact of an entire organization, this is your chance to lead and innovate. About the Team: The Builder Enablement team's mission is to make high-quality, AI-assisted shipping the default for every builder at Gusto. We own the design system, but also own how it gets expressed to AI tools and builders. Most of our focus is on AI tooling and enablement, such as: building MCP servers, agent skills, prompt engineering, eval systems, and experiments that make LLMs produce compliant, high-quality output. This is a great time to join to help define the direction for the team as we tackle the new challenges and opportunities that AI presents for the frontend at Gusto! Here’s what you’ll do day-to-day: Build and maintain AI tooling (MCP servers, agent skills, prompts) that enables builders to ship with the design system Develop tools to ensure that the quality, performance, and accessibility of Gusto’s reusable components continuously improve Develop tools to expand the pool of contributors and quality of contributions to Gusto’s frontend Run experiments to test hypotheses about what makes AI-assisted building better Shadow builders to understand real workflows and proactively fix blockers Partner with designers to build and maintain a system of reusable components, tokens, patterns, and documentation that empowers all of Gusto Develop eval systems to measure AI output quality against design system standards Communicate visibly and educate widely to technical and non-technical audiences Here’s what we're looking for: 10+ years of technical experience in a frontend engineering role Highly proficient in HTML, CSS, JavaScript, React, TypeScript Experience building developer tooling, plugins, or AI-powered tools Familiarity with LLM ecosystems (prompt engineering, MCP, agent skills, or similar) Experiment-driven mindset: comfortable framing hypotheses, scoping small tests, measuring outcomes Strong history of cross-functional collaboration with Design and/or other non-technical teams Experience in building UI components that are modular, composable, flexible, maintainable, and well-documented Experience with a JavaScript testing library for unit, integration, and end-to-end validation Appreciation for a collaborative, test-driven environment Experience turning wireframes and mockups into responsive, accessible, tested code Passionate about creating inclusive, accessible experiences for everyone Familiar with emerging trends in frontend development, including the various approaches to styling (CSS Modules, CSS-in-JS, Sass, etc.), component libraries (Material UI, Carbon, Polaris, and Lightning), accessibility tooling (axe), observability (RUM, Synthetic Testing), and AI (MCPs, prompting, evals, agents, etc.) Comfortable being visible and communicative Our cash compensation amount for this role is targeted at $225,000/yr to $275,000/yr for San Francisco, CA. Stock equity is additional. Final offer amounts are determined by multiple factors including candidate experience and expertise and may vary from the amounts listed above. Gusto has physical office spaces in Denver, San Francisco, and New York City. Employees who are based in those locations will be expected to work from the office on designated days approximately 2-3 days per week (or more depending on role). The same office expectations apply to all Symmetry roles, Gusto's subsidiary, whose physical office is in Scottsdale. Note: The San Francisco office expectations encompass both the San Francisco and San Jose metro areas. When approved to work from a location other than a Gusto office, a secure, reliable, and consistent internet connection is required. This includes non-office days for hybrid employees. Our customers come from all walks of life and so do we. We hire great people from a wide variety of backgrounds, not just because it's the right thing to do, but because it makes our company stronger. If you share our values and our enthusiasm for small businesses, you will find a home at Gusto. Gusto is proud to be an equal opportunity employer. We do not discriminate in hiring or any employment decision based on race, color, religion, national origin, age, sex (including pregnancy, childbirth, or related medical conditions), marital status, ancestry, physical or mental disability, genetic information, veteran status, gender identity or expression, sexual orientation, or other applicable legally protected characteristic. Gusto considers qualified applicants with criminal histories, consistent with applicable federal, state and local law. Gusto is also committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans in our job application procedures. We want to see our candidates perform to the best of their ability. If you require a medical or religious accommodation at any time throughout your candidate journey, please fill out this form and a member of our team will get in touch with you. Gusto takes security and protection of your personal information very seriously. Please review our Fraudulent Activity Disclaimer. Personal information collected and processed as part of your Gusto application will be subject to Gusto's Applicant Privacy Notice.