Design Affirm's consumer loan servicing platform
Last updated: August 6, 2025
Quick Overview
Design a platform that manages the full lifecycle of consumer loans from origination through payoff, including payment processing, statement generation, customer service tools, and collections workflows.
Affirm
August 6, 202511
6
4,508 solved
Design a platform that manages the full lifecycle of consumer loans from origination through payoff, including payment processing, statement generation, customer service tools, and collections workflows.
Loan servicing is the backbone of Affirm's operations. This question evaluates your ability to design complex stateful systems with regulatory requirements and long-running business processes that span months.
What the Interviewer Expects
- Model the complete loan lifecycle with clear state transitions
- Design payment processing for scheduled, manual, and early payoff scenarios
- Include statement generation and regulatory reporting
- Design customer service tools for loan inquiries and modifications
- Address collections workflows for delinquent accounts
Key Topics to Cover
How to Approach This
- Start by clarifying functional and non-functional requirements with the interviewer.
- Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
- Draw a high-level architecture first, then deep dive into 1-2 critical components.
- Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
- Address failure scenarios, monitoring, and how the system handles 10x traffic spikes.
Possible Follow-up Questions
- How would you handle a partial early payoff and recalculate remaining installments?
- How do you generate end-of-year tax documents (1099-INT) for consumers who paid interest?
- What happens when a consumer files for bankruptcy?
- How would you migrate loans from a legacy system to this new platform?
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Practice System Design ProblemsSample Answer
Loan Lifecycle Model
A loan goes through these states: Originated, Active, Delinquent, In Collections, Paid Off, Charged Off, Settled. Origination creates the loan record...
Payment Processing Engine
The payment engine handles three scenarios: **Scheduled payments**: A scheduler identifies loans with payments due today and enqueues them for proces...
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