Staff Software Engineer, Payroll Platform

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 500,000 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: We’re hiring a Staff Software Engineer to join Gusto’s Payroll Platform team, where you’ll build backend product infrastructure that powers payroll experiences across Gusto. This is a fully backend role focused on designing and evolving internal APIs and services used by other product teams to deliver accurate, compliant, and scalable payroll. You’ll own complex technical problems end-to-end, partner closely with other engineering teams, and help raise the bar on how payroll capabilities are built and consumed across the company. About the Team: The Payroll Platform team builds the foundational services that make payroll possible at Gusto. Our customers are internal product teams building payroll, time, contractor, and accountant experiences, as well as external partners through Gusto Embedded Payroll. We focus on creating reliable, performant, and well-designed APIs that abstract away payroll complexity and enable teams to move faster with confidence. Our work sits at the intersection of backend product engineering, developer experience, and large-scale systems in a highly regulated domain. Here’s what you’ll do day-to-day: • Design, build, and maintain backend services and APIs that support core payroll workflows and are consumed by multiple Gusto engineering teams • Own a primary domain within the Payroll Platform, taking responsibility for system health, correctness, scalability, and long-term evolution • Act as a technical partner to other engineering teams, collaborating closely to understand their needs, guide platform adoption, and co-design solutions that scale across use cases • Author and drive architecture and design documents, contributing to technical direction while balancing near-term delivery with long-term platform goals • Improve system performance, reliability, and observability as we scale payroll processing for hundreds of thousands of businesses • Collaborate cross-functionally with Product, Design, Data, Compliance, and Operations to deliver compliant and customer-impacting solutions • Routinely leverage AI-assisted development tools to accelerate development, improve code quality, and documentation, and help normalize and spread effective usage across the team. Here’s what we're looking for: • • 8+ years of professional software engineering experience, with a strong focus on backend development • Experience building and scaling internal platforms, shared services, or foundational APIs that support multiple product teams • Proven ability to work independently on ambiguous problems, from understanding the business need through delivery and iteration • Strong system design skills, including experience with performance optimization, scalability, and reliability in production systems • Actively uses AI-assisted development tools (LLMs, Claude Code, Cursor) in daily engineeri