Affirm

Senior Software Engineer, Back-end (Fraud)

Remote Checkout role with clear candidate location fit.

PostedRecently added

Eligible countries37 accepted countries

Seniority signalSenior

Work settingRemote

Accepted candidate locations

AlbaniaAustriaBelgiumBulgariaCroatiaCyprus+31 more

AWS CI/CD Kubernetes PostgreSQL Python REST Snowflake SQL

Role overview

Senior Software Engineer, Back-end (Fraud)

Requirements and responsibilities

Readable role content extracted into sections for faster review.

Details

You will 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.
You will 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.
You will build and evolve the platform and tooling that let Affirm launch fraud decisioning in a new country quickly—turning market-by-market setup (rules, models, and vendor configuration) into a repeatable, low-friction path so launches scale sub-linearly with the number of markets.
You will integrate region-specific fraud and risk vendors and help operationalize the machine learning and AI signals that power real-time decisioning, while using modern AI tooling to move faster as an engineer.
You will support peers and stakeholders across the product development lifecycle - collaborating with Product, Machine Learning, Analytics, and Fraud Strategy, articulating technical constraints, and partnering on decisions that properly weigh risks and trade-offs.
You will 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.
You will foster a culture of quality and ownership - setting and improving code review and design standards, mentoring teammates, and leading by example.
On-Call Rotation - There would be an on-call rotation for this role as a requirement.
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 - every Affirm engineer builds with tools like Claude Code and most PRs are co-authored with AI, so directing and orchestrating AI and excelling in the reviewer's seat (setting intent, critically evaluating generated code, and owning its correctness, quality, and security) is a core expectation.
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, with a strong understanding of risk, compliance, and operational constraints. (nice to have)
Health care coverage - Affirm covers all premiums for all levels of coverage for you and your dependents
Flexible Spending Wallets - generous stipends for spending on Technology, Food, various Lifestyle needs, and family forming expenses
Time off - competitive vacation and holiday schedules allowing you to take time off to rest and recharge
ESPP - An employee stock purchase plan enabling you to buy shares of Affirm at a discount