Senior Staff Software Engineer, Gusto Agent & Partner Experiences (API)

Denver, CO - Hybrid · New York, NY - Hybrid · San Francisco, CA - Hybrid · 12+ years experience · Hybrid · Posted Oct 15, 2026

At a glance

Experience: 12+ years experience
Workplace: Hybrid
Location: Denver, CO - Hybrid · New York, NY - Hybrid · San Francisco, CA - Hybrid

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.

As a Senior Staff Software Engineer on the Agent & Partner Experiences team, you'll be a key technical leader responsible for influencing the team and broader organization as we build and scale our platform.
You'll do this through a combination of hands-on development in our complex Ruby on Rails codebase and guiding others to deliver a high quality platform experience.
You’ll sit at the bridge between our API and AI world - turning a payroll platform built for developers into one that agents can reason about and act through.

Identify and solve high-impact problems involving technical and organizational complexity that requires understanding and coordination across multiple domains.
Design the API contracts and agent facing tools our partners and AI agents build on, including what a good interface looks like when the caller is an agent model.
Engage directly with our developer-customers and internal agent partner to deliver a remarkable payroll product.
Ship code. Clean, tested, and performant.
Level up the craft of software engineering across the organization by providing technical guidance and mentoring.
Inform and maintain best practices for reliability and observability for the team.
Troubleshoot and resolve production issues.

12+ years of professional software development experience. You have been a technical owner for organization-wide engineering initiatives and have played a role in scaling engineering organizations.
You are a Ruby and Rails expert. You have navigated massive Rails applications, worked with Ruby across multiple codebases, and are comfortable working at multiple layers of abstraction.
You've designed and built platforms and public-facing APIs, and have a strong understanding of how to build for reliability and performance at scale.
You've spent time mentoring and raising the technical bar for the entire organization. Others look to you for guidance on how to tackle ambiguous problems and handle competing priorities.
You think in terms of business priorities and know about how to orient your team around the right technical goals for the business as well as how to convey technical constraints and needs to business leaders.

Payroll domain experience: Payroll, tax or fintech experience is a real head start.
Agent facing tooling: Experience designing interfaces consumed by a model - MCP servers, tool and function definitions or an integration path for AI providers.
GraphQL at scale: You’ve been a client of GraphQL - writing efficient queries, building the query construction and data mapping layer around them, and reasoning about performance when you don’t own the resolvers.

Employees based in Denver, San Francisco, and New York City office locations will be expected to work from the office on designated days approximately 2-3 days per week.
When approved to work from a location other than a Gusto office, a secure, reliable, and consistent internet connection is required.
We expect regular and predictable attendance, whether you're working in-office, hybrid, or fully remote.