Senior Software Engineer (Fraud)

Affirm is a company reinventing credit to make it more honest and friendly by offering buy now, pay later solutions without hidden fees or compounding interest. The Fraud Engineering organization builds software to detect and respond to fraud strategically, supporting business growth while protecting customers and merchants. The Fraud International Team (FIT) extends Affirm's Fraud Decisioning System internationally across markets such as Canada, the UK, and Australia, focusing on real-time fraud decisioning and risk vendor integration.

• 5+ years of experience building backend systems at scale using Python or Kotlin.
• Experience with distributed systems and infrastructure using AWS, MySQL/PostgreSQL, and Kubernetes.
• Strong system design skills with a track record of delivering maintainable and extensible services.
• Proficiency in SQL and working with data-rich environments.
• Familiarity with CI/CD practices and safe production deployments.
• Strong written and verbal communication skills for distributed teams.
• Experience with AI-driven engineering tools, including code co-authoring with AI.
• A proactive, ownership-driven mindset focused on learning and team success.

Nice to have:

• Experience with Snowflake, dbt, Airflow, or Chronosphere.
• Background in fraud prevention, risk systems, or real-time decisioning.
• Experience building for multiple markets or internationalization/localization.
• Experience in fintech or highly regulated environments with understanding of risk, compliance, and operational constraints.

• Own and deliver quarterly team goals, leading engineers through ambiguity and supporting delivery.
• Design and implement real-time fraud decisioning services and APIs in Python or Kotlin.
• Build and evolve platform tooling to enable scalable launches of fraud decisioning in new countries.
• Integrate region-specific fraud and risk vendors and operationalize machine learning and AI signals for decisioning.
• Collaborate with Product, Compliance, Machine Learning, Analytics, and Fraud Strategy teams throughout product development.
• Support system operations by creating and monitoring metrics, escalating issues, and participating in on-call duties.
• Foster a culture of quality and ownership by setting code review and design standards and mentoring teammates.

This job role is remote within Poland. The job description is not a contractual document and has no binding force. Data processing is managed by Affirm as stated in their information clause.