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

Gusto•San Francisco, NY

2d•Hybrid

About The Position

As a Senior Staff Software Engineer on Gusto’s Agent & Partner Experiences team, you will be a key technical leader influencing the team and broader organization as it builds and scales its platform. The work combines hands-on development in a complex Ruby on Rails codebase with technical guidance to help others deliver a high-quality platform experience. The role bridges APIs and AI, making a payroll platform built for developers usable by agents that reason about and act through it. The Agent & Partner Experiences platform enables developers to embed payroll in their own software through Gusto APIs and enables AI agents to act on payroll on customers’ behalf. It makes Gusto’s payroll infrastructure available to third-party developers and agents, supporting products across vertical SaaS, fintech, neobanks, and AI-native businesses.

Requirements

12+ years of professional software development experience.
Experience as a technical owner for organization-wide engineering initiatives and a role in scaling engineering organizations.
Expertise in Ruby and Rails, including navigating large Rails applications, working with Ruby across multiple codebases, and working at multiple layers of abstraction.
Experience designing and building platforms and public-facing APIs.
Strong understanding of building for reliability and performance at scale.
Experience mentoring and raising the technical bar across an organization, and guiding others through ambiguous problems and competing priorities.
Ability to connect technical goals to business priorities and communicate technical constraints and needs to business leaders.

Nice To Haves

Payroll, tax, or fintech experience.
Experience designing interfaces consumed by models, such as MCP servers, tool and function definitions, or integration paths for AI providers.
GraphQL experience, including writing efficient queries, building query-construction and data-mapping layers, reasoning about performance without owning resolvers, and influencing API schemas owned by other teams.

Responsibilities

Identify and solve high-impact problems involving technical and organizational complexity across multiple domains.
Design API contracts and agent-facing tools for partners and AI agents, including interfaces suited to agent models.
Engage directly with developer-customers and internal agent partners to deliver a strong payroll product.
Write clean, tested, performant code and ship it.
Provide technical guidance and mentoring to raise software engineering craft across the organization.
Inform and maintain team best practices for reliability and observability.
Troubleshoot and resolve production issues.