Senior Fullstack Engineer, Payments

## About the role We're looking for a Senior Fullstack Engineer who wants to build the financial engine of our platform. You're not just building a checkout flow; you're powering the liquidity that makes this marketplace work. You'll join a high-impact team responsible for our custom double-entry ledger, payment provider integrations, and our core lending products. If you have a "measure twice, cut once" mindset for backend integrity but still move with a bias toward action on the frontend, you'll thrive here. ## Responsibilities - Engineer Financial Integrity: Build and maintain our custom-built double-entry ledger system to ensure every cent is accounted for across the platform. - Own Lending Infrastructure: Design and scale our lending products—from the logic of credit disbursements to the automated lifecycle of loan management. - Architect Integrations: Design and implement robust integrations with payment gateways and banking partners, ensuring 99.99% reliability and seamless reconciliation. - Own the UX of Money: Create high-trust user interfaces for payments and lending that make complex financial actions feel simple, transparent, and secure. - Balance Rigor with Speed: Make thoughtful trade-offs between rapid feature shipping and the uncompromising correctness required for financial systems. - Be a Multiplier: Level up the team through rigorous code reviews, technical documentation, and mentorship. ## Requirements - Are Obsessed with Correctness: You understand that in payments, "mostly working" is a failure. You think deeply about idempotency, race conditions, and data consistency. - Think Like a Product Owner: You don't just build a "pay button"; you understand the flow of funds and how to communicate financial status clearly to the user. - Love Building Infrastructure: You're energized by the challenge of building a ledger or a lending engine from the ground up. - Are Pragmatic: You know when to build a custom internal solution and when to leverage a third-party API to get the job done. ## What You Bring to the Table - 5+ years of experience with a heavy focus on backend systems (Python, Postgres, AWS) and a proven ability to build modern frontends (React, TypeScript). - Fintech or Payments experience: You've worked with ledgers, payment processors, or lending products and understand the complexities of moving money. - Database Mastery: You are an expert in SQL and relational database design—you know how to write a transaction that won't fail under load. - Fullstack Ownership: A track record of taking a complex financial feature from a technical design doc all the way to a polished UI in production. - Bonus: Experience with distributed systems, credit/risk modeling, or the alternative asset space. ## What We Offer - A seat at the table to help shape the future of Alt and the alternative asset space - Autonomy and ownership on projects that matter - $100/month work-from-home stipend - $200/month wellness stipend - WeWork office stipend - 401(k) retirement benefits - Flexible