Senior Staff Full-Stack Engineer - Ruby & React

At Gusto, we are on a mission to grow the small business economy by simplifying payroll, health insurance, HR, and financial benefits for over 500,000 nationwide businesses.

As a Senior Full-Stack Engineer on the Money Planning team, you will build and own the core platform services and user interfaces that empower over one million savers and entrepreneurs to manage their retirement funds—including 401(k)s, IRAs, portfolios, and withdrawals. In this hands-on engineering role, you will take backend microservices, GraphQL APIs, and React interfaces end-to-end—partnering with Product, Design, Compliance, and Operations to navigate complex financial rules and edge cases. You will also embed AI tools into daily engineering workflows and leverage AI-native capabilities to simplify retirement decision-making for savers.

Key Responsibilities

• End-to-End System Ownership: Design, build, test, and maintain full-stack capabilities allowing savers and business owners to manage contributions, portfolio allocations, and retirement distributions.
• Backend Architecture & APIs: Architect scalable backend services and asynchronous message pipelines using Ruby on Rails, GraphQL, and Sidekiq/Kafka.
• Frontend User Experiences: Develop modern, highly reliable web applications in React, translating complex financial workflows into accessible interfaces.
• AI-Native Engineering: Utilize AI tools continuously in daily workflows to shorten feedback loops, and evaluate product features where AI can proactively guide savers through complex decisions.
• Cross-Functional Collaboration: Partner with Product Management, Compliance, Design, and Operations to write clear software specifications accounting for strict financial regulations.
• Operational Excellence: Debug production incidents, elevate platform observability, optimize database performance, and improve automated testing coverage.

Requirements

Full-Stack Software Engineering Depth

• 8+ years of professional software engineering experience building and shipping production-grade platforms or products.
• Core Technology Proficiency:
  • Backend: Ruby on Rails experience is required.
  • Frontend: Strong experience with large modern JavaScript/TypeScript applications (e.g., React).
  • API & Data Querying: Strong experience with GraphQL and RESTful service design.
  • Asynchronous Systems: Hands-on experience with message-based, event-driven architectures (Sidekiq, Kafka, or similar).
• Demonstrated experience owning systems end-to-end, including production operational support, monitoring, and debugging.
• Proven track record of collaborating with cross-functional partners (PMs, Designers, Compliance) to deliver scoped technical projects.
• Clear, pragmatic, and execution-focused engineering approach with strong written and verbal communication skills.

Work Logistics

• Ability to attend in-office onboarding at a designated Gusto office.
• Adherence to local hybrid expectations (2–3 days/week in Denver, SF, or NYC) or secure remote work setup.

Preferred Qualifications

• Direct domain experience in FinTech, wealth management, 401(k)/IRA recordkeeping, or banking infrastructure.
• Practical experience with AI coding assistants, automated test generation, and LLM-assisted development workflows.
• Experience modernizing legacy Rails applications or decomposing monoliths into event-driven microservices.

Total Rewards & Benefits

• Base Pay & Equity: Competitive base salary + equity compensation in the form of Restricted Stock Units (RSUs).
• Comprehensive Healthcare: Medical, dental, and vision insurance for employees and dependents.
• Retirement & Financial Perks: 401(k) retirement plan support, flexible spending accounts, and employee discount programs.
• Workplace & Connection: Hybrid/remote work flexibility, professional growth stipends, and an inclusive work environment.