Affirm
Mid
Build the money-movement systems behind Affirm's debit card and BNPL flows
Affirm's Money Movement & Card Ledger team builds the systems that move money, integrate bank data, and manage merchant data behind Affirm Card and its buy-now-pay-later financing. The interview looks for someone with about 2.5+ years of backend experience in Python or Kotlin who can design correct, scalable APIs, take ownership of a piece of a larger project, and hold up their end during on-call.
Step into this interview
Free · a live voice mock calibrated to this exact role
What this interview tests
- API design for financial/ledger systems (correctness, idempotency)
- Python or Kotlin backend proficiency
- Distributed systems building blocks (AWS, MySQL, Kubernetes)
- Breaking down and phasing larger projects
- On-call and operational ownership
- Cross-functional communication with product/design/analytics
Common question themes
Design an API for tracking money movement between a bank and a merchant
How do you ensure idempotency when a payment or ledger entry might be retried
Tell me about a time you had to debug someone else's code
Describe breaking a large project into deliverable phases
How would you monitor a critical money-movement service for issues