Senior Full-Stack Software Engineer

The role

You will design, build, and ship full stack features across web and mobile surfaces. You will own projects end to end, from scoping requirements to deployment, and integrate third party payment and financial APIs.

What you will do

• Design, build, and ship full stack features across web and mobile surfaces.
• Own projects end to end from scoping to deployment.
• Integrate third party payment and financial APIs.
• Build scalable, high performance services for real money movement.
• Maintain code quality through clean abstractions, tests, and code review.
• Collaborate with product, design, and operations.

Required qualifications

• Deep experience with TypeScript and Node.js.
• Production experience with React Native.
• Experience owning complex product changes from idea through launch.
• Deep comfort debugging across the stack.
• Solid understanding of security best practices.
• Strong sense of code quality, including testing, readability, and maintainability.
• Clear written and verbal communication.
• High tolerance for ambiguity.

Nice to have

• Familiarity with the Expo ecosystem and modern mobile build pipelines.
• Experience in EITHER traditional fintech integrations (Stripe, Plaid, ACH rails) OR blockchain infrastructure (especially Solana in a production environment).
• Prior startup experience where you were an early engineer and had meaningful product ownership.

About the company

Fin is a next-generation payments platform built for high-value, global, and instant transactions. It is a Series A-stage company backed by Sequoia, Circle, and other notable investors.