Backend Engineer

Backend Engineer

About xPay

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 that 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 sectors such as EdTech and travel, processing millions through us every month.

About the Role

We’re looking for a Backend Engineer to build the services powering xPay’s global payments infrastructure. You’ll own features end to end, from design and development to production deployment and on-call support, working closely with product, engineering, and the founders.

What You’ll Do

• Design, build, and ship production-grade backend services and APIs using Java 21, Spring Boot, and MongoDB, working with Redis, ClickHouse, and AWS services including ECS, SQS, S3, and SES.

• Build and scale multi-currency payment systems that support complex global payment flows.

• Own features throughout their lifecycle, from requirements and technical design to deployment, monitoring, and on-call support.

• Work closely with product and engineering to turn ideas into reliable features quickly.

• Design MongoDB data models, indexes, and update patterns that balance performance, consistency, and scalability.

• Improve reliability and performance across services, databases, and APIs.

• Debug production issues, identify bottlenecks, and drive lasting improvements to architecture and operations.

What We’re Looking For

• 4–6 years of backend engineering experience, preferably at an early-stage startup or in a small team with end-to-end ownership.

• Strong production experience with Java, Spring Boot, and MongoDB. Hands-on experience with all three is mandatory.

• Solid MongoDB data modelling skills, including indexing, transactions versus atomic updates, and versioning.

• Strong fundamentals in API design, system design, and distributed systems.

• Experience building, scaling, and maintaining production-grade backend systems.

• Strong problem-solving and debugging skills, with a focus on reliability and performance.

• Clear communication, a high degree of ownership, and the ability to move quickly in a high-growth environment.

Why Join xPay?

• Global payments infrastructure: Solve complex problems across countries, currencies, and payment flows.

• Direct access to founders: Help shape product decisions, engineering practices, and architecture.

• Meaningful equity: Join an early team and share in the value you help create.

• High ownership and impact: Build critical systems that directly affect xPay and its merchants.