Senior Software Engineer, Backend (International)

At Affirm, we exist for the moments that matter—giving people a clear, predictable way to pay over time, with no hidden fees, no surprises, and no tradeoffs on what matters most.

The Payments International Engineering team builds and operates the systems that enable bank and card payments across Affirm’s international markets. Based in Europe, with teammates across the UK, Spain and Poland, we give customers familiar, local ways to pay, while building shared capabilities that make expansion into each new country easier.

Our work spans improving existing payment experiences and building the foundations for launches in new countries. We solve challenges across currencies and local customer needs, creating reusable solutions that support Affirm’s international ambitions. We work closely with product and engineering teams across Affirm, connecting the customer experience with the financial systems behind it.

We own our work from design through to production, combining the pace of international expansion with the reliability, security and operational readiness that payments demand. Testing, monitoring and supporting our systems are integral to how we build. As a growing team, we also shape the architecture, tools and engineering practices that support this growth.

Joining Payments International means helping build the foundations of a global payments platform, with a direct connection between the systems we create and the customers Affirm can serve.

What you’ll do

• You will be responsible for owning and delivering quarterly goals for your team, leading engineers on your team through ambiguity to solve open-ended problems, and ensuring that everyone is supported throughout delivery.

• You will support your peers and stakeholders in the product development lifecycle by collaborating with product management, design & analytics by participating in ideation, articulating technical constraints, and partnering on decisions that properly consider risks and trade-offs.

• You will proactively identify project, process, technology or business issues, advocate for them, and lead in solving them.

• You will support the operations and availability of your team’s artifacts by creating and monitoring metrics, escalating when needed, and supporting “keep the lights on” & on-call efforts.

• You will foster a culture of quality and ownership on your team by setting or improving code review and design standards for your team, and advocating for them beyond your team through your writing and tech talks.

• You will help develop talent on your team by providing feedback and guidance, and leading by example.

What we look for

• You have 4+ years of experience designing, developing and launching backend systems at scale using languages like Python or Kotlin.

• You have a track record of developing highly available distributed systems using technologies like AWS, MySQL and Kubernetes.

• You have experience defining a technical plan for the delivery of a significant feature or system component with an elegant, simple and extensible design. You write high quality code that is easily understood and used by others.

• You are proficient at making significant changes in a large code base, and have developed a suite of tools and practices that enable you and your team to do so safely.

• Your experience demonstrates that you take ownership of your growth, proactively seeking feedback from your team, your manager, and your stakeholders.

• You have strong verbal and written communication skills that support effective collaboration with our global engineering team.