Software Engineer, Expansion

Position: Staff Software Engineer, Expansion Experiences
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  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.

We're looking for a seasoned full-stack software engineer to join Gusto's Expansion Experiences team, which helps small business owners discover and adopt more of what Gusto offers, such as upgrading to Plus or Premium, adding 401(k) or health insurance, or finding the features that fit their business.

As a Staff Software Engineer, you'll operate across the full product lifecycle, shaping experiments and features from early concept through launch and long-term iteration. That means writing clean frontend code, designing and building reliable backend APIs, and bringing real product and customer-experience judgment to the table. We want engineers who ask whether an idea will actually change customer behavior, not just whether it matches the spec.

If you're drawn to work that combines technical craft with real-world impact, helping power the livelihoods of millions using Gusto products, join us!

Here's what you'll do day-to-day:

Design, build, and test customer-facing experiences across recommendations, nurture campaigns, booking flows, and the plan upgrade/retention experience

Run structured experiments (A/B tests, phased rollouts) to validate whether a change moves conversion, adoption, or retention, and iterate quickly based on results

Design and build reliable backend APIs and data models that support personalization, recommendations, and multi-step customer journeys

Mentor other engineers and raise the bar on technical execution, product quality, and responsible use of AI across the team.

Collaborate with our Product Management, Design, Data, and Platform Engineering teams to understand customer pain points, come up with solutions, and then prototype, iterate, and launch

Here's what we're looking for:

Successful applicants typically have 8+ years of software development experienceA product-minded engineer who starts from the customer problem and the metric that matters, not just the ticket, and is comfortable proposing a different approach when the data calls for it Experience building scalable solutions that eliminate customer pain, ideally in a growth, lifecycle, or conversion-focused context (onboarding, upsell flows, personalization, or recommendations) — or demonstrated ability to think this way Experience owning multi-quarter projects that solve complex engineering problems and make measurable customer impact at scale

Comfort designing and interpreting experiments, and working with ambiguous or evolving requirements

Ability to mentor engineers to maximize their performance and impact

Experience with large-scale refactors, performance and reliability issues, and a strong sense of ownership over all aspects of your product area Experience leveraging AI tools or systems to accelerate development, improve testing, and deliver new product capabilities

Others:

Experience in, or interest working in, Ruby on…