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Salary: USD 213,000 - 278,000 / annual
Gusto is seeking a Senior Staff Software Engineer to join the Agent & Partner Experiences team, a platform enabling developers to embed payroll directly into their software via APIs and allowing AI agents to act on payroll on customers' behalf. You will be a key technical leader responsible for influencing the team and broader organization as the company builds and scales this platform.
In this role, you will combine hands-on development in a complex Ruby on Rails codebase with guiding others to deliver a high-quality platform experience. You'll sit at the bridge between Gusto's API and AI worlds, transforming a payroll platform built for developers into one that AI agents can reason about and act through.
Day-to-day responsibilities include:
- Identifying and solving high-impact problems involving technical and organizational complexity that require understanding and coordination across multiple domains
- Designing API contracts and agent-facing tools that partners and AI agents build on, including interfaces optimized for agent model consumption
- Engaging directly with developer-customers and internal agent partners to deliver a remarkable payroll product
- Shipping clean, tested, and performant code
- Leveling up software engineering craft across the organization through technical guidance and mentoring
- Informing and maintaining best practices for reliability and observability
- Troubleshooting and resolving production issues
Gusto's Agent & Partner Experiences platform has taken the company's robust payroll infrastructure and made it available beyond Gusto itself—to third-party developers and AI agents acting on their customers' behalf. The vision is to enable anyone to build the best payroll product for their end customers, powering payroll for small and medium businesses across vertical SaaS, fintech, neobanks, and AI-native products.
Gusto supports more than 500,000 small businesses nationwide and has teams in Denver, San Francisco, and New York. The company is on a mission to grow the small business economy by handling payroll, health insurance, 401(k)s, and HR so owners can focus on their craft and customers. All full-time employees receive competitive base pay, benefits, and equity (RSUs).
AI is a fundamental part of how work gets done at Gusto. The company expects all team members to actively engage with AI tools relevant to their role and grow their fluency as the technology evolves.
Requirements:
- 12+ years of professional software development experience
- Technical ownership of organization-wide engineering initiatives and experience scaling engineering organizations
- Expert-level Ruby and Rails proficiency; experience navigating massive Rails applications and working across multiple layers of abstraction
- Platform design and public-facing API experience with strong understanding of building for reliability and performance at scale
- Demonstrated mentoring and technical bar-raising across entire organizations; others look to you for guidance on ambiguous problems and competing priorities
- Strong communication skills; ability to think in terms of business priorities and orient teams around the right technical goals while conveying technical constraints to business leaders
Bonus (optional):
- Payroll, tax, or fintech domain experience
- Experience designing interfaces consumed by AI models (MCP servers, tool and function definitions, AI provider integrations)
- GraphQL at scale experience, including efficient query writing, query construction and data mapping layers, and performance reasoning
