Senior Software Engineer, Back-end (Fraud)

Overview

Job Description

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.
• - Design and implement real-time fraud decisioning services and APIs in Python or Kotlin, extending Affirm's Fraud Decisioning System to markets beyond the US.
• - Build and evolve the platform and tooling that let Affirm launch fraud decisioning in a new country quickly.
• - Integrate region-specific fraud and risk vendors and help operationalize the machine learning and AI signals that power real-time decisioning.
• - Support peers and stakeholders across the product development lifecycle - collaborating with Product, Machine Learning, Analytics, and Fraud Strategy.
• - Support the operations and availability of your team's systems by creating and monitoring metrics, escalating when needed, and contributing to keep-the-lights-on and on-call efforts.
• - Foster a culture of quality and ownership - setting and improving code review and design standards, mentoring teammates, and leading by example.
• - Participate in an on-call rotation as a requirement.

Required Skills

• - 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 and a track record of delivering maintainable, extensible services.
• - Fluency with AI-driven engineering - directing and orchestrating AI and excelling in the reviewer's seat.
• - Proficiency in SQL and working with data-rich environments.
• - Familiarity with CI/CD practices and safe production deployments.
• - Strong written and verbal communication skills, especially in distributed teams.
• - A proactive, ownership-driven mindset with a focus on learning and team success.
• - Experience with Snowflake, dbt, Airflow, or Chronosphere (nice to have).
• - Background in fraud prevention, risk systems, or real-time decisioning (nice to have).
• - Experience building for multiple markets or regions - internationalization or localization (nice to have).
• - Experience working in the fintech sector or other highly regulated environments (nice to have).

Benefits

• - 100% subsidized medical coverage, dental and vision for you and your dependents.
• - Flexible Spending Wallets for tech, food and lifestyle.
• - Away Days - wellness days to take off work and recharge.
• - Learning & Development programs.
• - Parental benefits.
• - Employee Resource & Community Groups.
• - Visa sponsorship available for this role.