Senior Fullstack Engineer, Payments

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.

• 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.

• 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.

• 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.

• 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 vacation policy
• Generous paid parental leave
• Competitive healthcare benefits, including HSA, for you and your dependent(s)

Base salary range: $140,000-$180,000, plus equity. Offers may vary based on experience, location, and other factors.