Senior Software Engineer, Backend (Fraud)

Affirm is reinventing credit to make it more honest and friendly, giving consumers the flexibility to buy now and pay later without any hidden fees or compounding interest.

Identity International is a newly established team created to accelerate Affirm’s international expansion - one of the company’s top priorities. Our vision is to become a trusted, self-sufficient team that drives customer identity capabilities end-to-end across international markets.

The team’s scope includes building and expanding Identity Data Management, Verification, and Decisioning capabilities for Europe, evaluating and integrating third-party KYC vendors, and ensuring alignment with global platform and operational standards. We operate at the intersection of technical depth, regulatory complexity, and cross-geo collaboration, making this an exciting opportunity for engineers who want to shape one of Affirm’s foundational processes.

By joining the team, you will directly influence how Affirm operates Identity in international markets - a challenge that is critical for both business growth and customer trust.

• 5+ years building backend systems at scale with Python or Kotlin.
• Experience with distributed systems on AWS, Kubernetes and MySQL/PostgreSQL.
• Proficiency in SQL and data rich environments.
• Strong system design skills and track record delivering maintainable services.
• Familiarity with CI/CD and safe production deployments.
• Experience with observability and incident response; participation in on-call rotations.
• Strong written and verbal English communication.

Nice to have:

• Kotlin
• AWS
• Kubernetes
• PostgreSQL
• SQL
• CI/CD
• Observability
• On call rotation

• Own and deliver quarterly team goals; lead engineers through ambiguity and drive execution.
• Design and implement backend services and APIs using Python or Kotlin within microservice and event-driven architecture.
• Build scalable fraud tooling and infrastructure in collaboration with Product, Compliance, Machine Learning and Fraud Ops.
• Improve system reliability and architecture; maintain high observability standards and participate in on-call rotation.
• Contribute to technical design, code quality and mentoring; represent team in cross-functional initiatives.