Senior Full-Stack Engineer (+ Equity) at VC-backed cross-border fintech startup

This is a job that Jill, our AI Recruiter, is recruiting for on behalf of one of our customers. She will pick the best candidates from Jack's network. The next step is to speak to Jack. Job Title Senior Full-Stack Engineer (Fintech Infrastructure) Salary Not Disclosed + Equity Company Description VC-backed cross-border fintech startup Job Description Own the end-to-end development of an API-first payments product within a high-velocity environment. You will build resilient provider integrations, manage real-time transaction flows, and architect scalable monitoring layers. This role is central to building the infrastructure for global money movement, requiring a deep focus on reliability, idempotency, and rapid iteration cycles. Location London, UK Why this role is remarkable Directly impact global financial infrastructure by building systems that move real money across international borders every day.Join a pre-Series A startup backed by top-tier venture capital firms, offering significant equity and early-stage growth potential.Work in a high-performance, in-person environment with a fast-shipping culture and 7-day iteration cycles. What You Will Do Design and ship complex payment provider integrations that handle high-volume transactions across multiple international corridors.Develop mission-critical monitoring and resilience layers, including retries and fallbacks, to ensure 24/7 transaction reliability.Communicate directly with institutional clients and providers to diagnose failures and optimize live payment flows. The ideal candidate Proven experience building and scaling production-grade payment systems, fintech products, or transaction processing engines.Strong proficiency in TypeScript, Node.js, and PostgreSQL with a backend-heavy, full-stack approach to software engineering.Exceptional resilience and problem-solving skills, comfortable managing live system failures and building automated recovery mechanisms. Who are Jack & Jill? Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support. And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate. How does this work? Jack's an AI agent for job searching and career coaching. He works for you.Jill is the AI recruiter working for the company. She recruits from Jack's network.If it's a match and the company wants to meet you, they'll make the intro. In the meantime, if you'd like, Jack will send you excellent alternatives. We never post fake jobs This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network. Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description. We appreciate this can make them look a bit suspect, but there isn't much we can do about it. Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.