Design Scalable Expense Violation Processing
Company: Rippling
Role: Software Engineer
Category: System Design
Difficulty: hard
Interview Round: Technical Screen
You now need to productionize the same corporate card policy system. Design a system that can process millions of expenses per day and tens of thousands of rules, while flagging both expense-level and trip-level violations.
Discuss:
- how expenses are ingested and evaluated,
- how rules are stored, versioned, and loaded efficiently,
- how to handle stateful trip-level limits,
- how to persist violations for audit and reporting,
- how to notify employees and managers about violations,
- how to scale the system, handle retries and idempotency, and support future rule types and API-based rule creation.
Quick Answer: This question evaluates a candidate's competency in large-scale system design, covering distributed architectures, high-throughput ingestion and evaluation pipelines, rules storage and versioning, stateful trip-level processing, persistence for auditability, notification workflows, and operational concerns like scaling, retries and idempotency.