Staff Software Engineer, Invoicing and Billing

Gusto is on a mission to grow the small business economy, handling payroll, health insurance, 401(k)s, and HR for over 500,000 small businesses nationwide. With teams in Denver, San Francisco, and New York, Gusto is building a workplace that reflects the people it serves. AI is a fundamental part of how work gets done at Gusto; all team members are expected to actively engage with AI tools relevant to their role.

As a Staff Software Engineer on the Invoicing and Billing platform, you will operate across the full lifecycle of Gusto's commerce systems: shaping architecture early in the design process, improving and maintaining a high-throughput transactional billing platform, building self-service internal features and APIs, and owning performance long after launch. You will engineer the core commerce engine, enabling product teams to launch new products and support new billing models like multi-entity, multi-currency anniversary billing.

• Design, build, and test Gusto's core billing platform – usage jobs, subscriptions, orders, invoice generation, payments, reporting, accounting integrations.
• Mentor other engineers to solve complex technical problems at 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, prototype, iterate, and launch daily.

• Typically 8+ years of software development experience.
• Passion for creating scalable, efficient platforms.
• Experience leveraging AI tools or systems to accelerate development, improve testing, and deliver new platform capabilities.
• Curiosity and experimentation with emerging AI frameworks, applying best practices to evaluate and scale AI use safely.
• Experience building large high-throughput distributed systems.
• Experience in the Commerce domain: invoicing, commerce, payment processing, revenue recognition.
• Experience owning multi-quarter projects that solve complex engineering problems and make measurable user impact at scale.
• Experience with large-scale refactors, performance and reliability issues, and a strong sense of ownership.
• Ability to mentor engineers to maximize performance and impact.
• Experience in, or interest in working in, Ruby on Rails.
• Ability to communicate effectively across engineering teams and with business stakeholders.

Cash compensation is targeted at $163,000–$204,000 in Denver & most remote locations, and $197,000–$247,000 for San Francisco & New York. Stock equity is additional. All full-time employees receive competitive base pay, benefits, and equity (RSUs).

This role is based in San Francisco, CA and is Hybrid. Employees based in Denver, San Francisco, or New York are expected to work from the office on designated days approximately 2-3 days per week (or more depending on role). Travel to Gusto's office for onboarding is required.

Apply through the Gusto Greenhouse job posting.