Staff Software Engineer, Core AI Platforms

About the Role

Gusto is looking for seasoned full-stack software engineers to join the teams behind Gusto's AI product platforms — the shared systems that product teams build upon to serve small business owners every day.

As a Staff Software Engineer, you'll operate across the full lifecycle of foundational systems: deliver production AI agent systems — multi-agent orchestration, tool/workflow registries, agent-to-agent handoffs, human-in-the-loop escalation, and long-running conversation state, shaping architecture early in the design process, building self-service internal features and APIs, and owning their performance long after launch.

Responsibilities

• Design and maintain evaluation frameworks across offline and online environments — including golden datasets, LLM-as-judge pipelines, and production replay — while establishing regression gates and end-to-end observability and tracing for agent runs
• Design, build, and test Gusto core platform services – communications, reporting, dashboards, access, workflows, risk, payments, and compliance capabilities, among others
• Mentor other engineers to help solve some of the hardest technical problems in complex domains and at large scale
• Help scale one of the largest Ruby/Rails and Javascript/React applications in the world
• Collaborate with Product Engineering, Product Management, Data, and Design teams to understand customer pain points, develop solutions, and prototype, iterate, and launch daily
• Build platforms that engineering teams rely on and trust to deliver products that customers love

Qualifications

• 8+ years of software development experience
• Hands-on experience taking AI/LLM capabilities to production — agent orchestration, tool integration, retrieval, and evaluation/feedback loops
• AI fluency: fluent, daily use of AI coding assistants (e.g., Claude Code, or equivalent AI harness) across the development lifecycle with strong judgment on when to apply them and evaluate output quality
• Passion for creating scalable, efficient platforms for users
• Curiosity and experimentation with emerging AI frameworks, applying and sharing best practices safely across teams

Preferred Qualifications

• Experience in, or interest working in, Ruby on Rails
• Appreciation for a collaborative, test-driven environment
• Ability to build well-structured, maintainable, well-documented code
• Ability to effectively communicate across engineering teams and with business stakeholders

*Note: Two-day travel to a Gusto office for onboarding is required for this position.*