Fullstack Engineer

About us

xPay is a Y Combinator backed international payments company building an international payment gateway focused on cross-border payments — making it dramatically easier for businesses to move money across borders. Our customers are B2B SaaS companies who need fast, reliable, and cost-effective payment infrastructure to serve global users.These businesses are increasingly moving their international volumes from billion dollar companies to xPay as we expand our footprint across 180+ countries and support 25+ currencies. Since January 2025, we have grown 73× and now process over 1 million transactions every month.

Cross-border payments is a $200 trillion market. Our top customers include Publicly Listed, Series D and Series E companies across various sectors like EdTech and Travelling processing millions through us every month.

The Role

We're looking for a Fullstack Engineer to build the systems and interfaces that power global transactions for thousands of merchants. This is a hands-on role for someone who has thrived in an early-stage or small-team environment and gets energized by shipping features that directly move revenue for businesses across the world.

What You'll Do

• Build the core services and interfaces that drive high-scale, global payment flows - owning features end-to-end from API to UI
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• Work directly with product and design to ship features rapidly from idea to production, and contribute to refining our design system for visual consistency 
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• Design and ship frontend in React, TypeScript, Tailwind, and TanStack/React Query
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• Design and ship production-grade backend services in Java, Spring Boot, and MongoDB
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• Improve performance across the stack - from database queries and service latency to frontend rendering - through better patterns and architecture

What We're Looking For

• 5+ years of experience as a fullstack engineer, preferably at an early-stage startup or on a small team where you owned outcomes end-to-end
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• Strong working knowledge of React, TypeScript, Tailwind, and TanStack/React Query — we are not flexible on the frontend stack
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• Solid backend fundamentals — we use Java, Spring Boot, and MongoDB, but we're flexible here. If you're strong in another stack (Node.js, Go, Python, Kotlin, etc.) and willing to ramp up on ours, we'd love to talk
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• Comfort moving fluidly between backend and frontend within the same feature — solid instincts for API design, data modeling, and system tradeoffs
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• Strong sense of UX and visual design, and an eye for polished interfaces
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• Strong communication skills, curiosity, speed, and willingness to learn in a high-growth environment

Why this role is interesting

• Payments infrastructure at global scale - real, complex problems with immediate impact on thousands of merchants
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• Direct access to founders. Real influence on product and architecture. Clear path to grow into a senior or lead role
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• Meaningful equity. Early team member - we treat the role that way