Senior Frontend Engineer

About Finix Finix is building the global operating system for fintech, starting with payments. From startups to publicly traded companies, Finix processes tens of billions of dollars annually both in-store and online. Finix was founded in 2015 and is headquartered in San Francisco.

To date Finix has raised over $200M, including a $75M Series C led by Acrew Capital and Lightspeed Venture Partners and backed by American Express Ventures, Bain Capital Ventures, Homebrew, Inspired Capital, Visa, and others

As a Senior Frontend Engineer on our Frontend Engineering Team, you'll architect and build the core payment experiences that power thousands of businesses. You'll develop our comprehensive payments management dashboards and embeddable components that merchants integrate directly into their applications.

In this role, you'll drive the technical vision for customer-facing products from conception to production. You'll lead design and implementation decisions while ensuring our payment interfaces remain performant, secure, and intuitive as we scale. Our engineering team operates with high autonomy and ownership—each engineer makes meaningful contributions that directly impact customer success in our dynamic fintech environment.

Finix is looking for engineers who bring exceptional technical acumen, attention to detail, passion for growth, and an obsession with delivering an exceptional customer experience.

You Will: Build and maintain sophisticated payment dashboards and transaction management interfaces

Build performant, accessible, and reusable component libraries that scale across multiple products

Lead technical design sessions and drive frontend architecture decisions

Optimize application performance for high-volume financial data processing

Collaborate with Product, UX, and Engineering teams to translate complex payment workflows into intuitive user experiences

Mentor engineers and establish frontend development standards and best practices

You Are: Experienced in balancing rapid feature delivery with code quality, testing, and maintainability

Skilled at translating business requirements into scalable technical solutions

Proactive in monitoring live systems and troubleshooting production issues

Comfortable working with ambiguous requirements and driving clarity through technical discovery

Committed to knowledge sharing and building team capabilities through documentation and mentorship

You Have: 6+ years of production experience with modern web technologies (HTML, CSS/SCSS, JavaScript/TypeScript)

3+ years of hands-on React development in complex, data-heavy applications

Solid experience with state management solutions (Redux, Zustand, Recoil, or similar)

Strong background in testing strategies and frameworks

Experience building responsive, accessible web applications

Understanding of RESTful APIs and modern build tools

Bonus if you have: Experience in payments, fintech, fraud prevention, or financial services

Backend development experience with Java/Spring, Docker, Kubernetes, or AWS

Track record building secure, observable APIs and distributed systems

Experience with micro-frontend architectures or component library development