Senior Software Engineer, Backend (Identity International)

About the Position

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.

Affirm’s Identity team is mission-critical to the customer checkout experience. When a customer chooses Affirm, one of the first steps is an identity check, and our ability to make the right decision directly impacts conversion, revenue, fraud exposure, and regulatory compliance. Our team owns Identity for all markets outside North America, playing a key role in Affirm’s international expansion. We are responsible for KYC, user lifecycle management, and identity decisioning across multiple regulatory environments. This work is about shaping how Affirm adapts its core Identity platform to new market dynamics, customer expectations, and compliance requirements.

We are a team of six engineers based across Spain and Poland. We are looking for a Senior Software Engineer who can turn ambiguous business and customer problems into reliable, well-designed technical solutions.

In this role, you will help shape our quarterly technical direction, translate team goals into concrete projects, and identify cross-cutting risks, tradeoffs, and opportunities. You should be comfortable designing across system boundaries, driving collaboration with partner teams, and advocating for technical investments that improve long-term execution. We’re looking for someone who takes ownership beyond shipping code: raising code quality and review standards, making performance, availability, and scale tradeoffs explicit, and improving the operational health of the systems they own. You’ll help reduce toil, create useful playbooks, mentor engineers, support new hires and interns, and contribute to high-signal hiring.

Most importantly, we’re excited to work with someone who leaves things better than they found them, communicates clearly across audiences, uses customer feedback to influence technical plans, and helps the team continuously improve.

This is a deeply technical, hands-on coding role where feature velocity and operational excellence go hand-in-hand. You’ll spend most of your week in the codebase - leveraging AI tools to write robust Kotlin and Python, ship impactful features, investigate complex production issues, and keep our systems rock-solid and reliable. This is a high-visibility, high-impact role for someone who wants to work on foundational systems that directly enable Affirm’s global growth.

Responsibilities

• Own and deliver quarterly goals for your team, leading engineers through ambiguity to solve open-ended problems, and ensuring that everyone is supported throughout delivery.
• Support 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.
• Proactively identify project, process, technology, or business issues, advocate for them, and lead in solving them.
• 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.
• 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.
• Help develop talent on your team by providing feedback and guidance, and leading by example.

Requirements

• 4+ years of experience designing, developing, and launching backend systems at scale using languages like Python or Kotlin.
• Experience developing highly available distributed systems using technologies like AWS, MySQL, and Kubernetes.
• 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.
• Proficiency 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.
• Experience demonstrates that you take ownership of your growth, proactively seeking feedback from your team, your manager, and your stakeholders.
• Strong verbal and written communication skills that support effective collaboration with our global engineering team.

We Offer

• Competitive salary range: £120,000–£168,000 GBP per year.
• Comprehensive benefits package including 100% subsidized medical coverage, dental, and vision for you and your dependents.
• Monthly stipends for health, wellness, and tech spending.
• Flexible time off and generous holiday calendars.
• Opportunity to own a piece of what you build through our employee stock purchase plan (ESPP).

About the Company

Affirm is proud to be a remote-first company. Most roles can be done from almost anywhere within the country of employment. Some positions may occasionally require in-person work at an Affirm office, and a few are office-based due to the nature of the work. All new hires will be invited to attend an in-person onboarding experience.

Our benefits reflect our commitment to care, transparency, and flexibility. Here are a few highlights:

• Health coverage at no cost: We cover 100% of premiums for employees and their dependents.
• Spending stipends: Monthly stipends support your tech setup, and the ability to choose health and wellness options that are right for you.
• Time off to recharge: Flexible time off and generous holiday calendars help you rest when you need to.
• Own a piece of what you build: Our employee stock purchase plan (ESPP) lets you buy Affirm stock at a discount.

We’re committed to providing an inclusive interview process, including accommodations for candidates with disabilities. If you need support, we’re happy to help.

For positions based in San Francisco or Los Angeles: Affirm considers qualified applicants with arrest and conviction records, as required by law.

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