Design a Visa-like payment processing system

Company: Databricks

Role: Software Engineer

Category: System Design

Difficulty: hard

Interview Round: Technical Screen

Quick Answer: This question evaluates a candidate's ability to design a secure, low-latency card payment processing network, testing knowledge of distributed systems, transaction semantics (authorization, capture, refunds, reversals), idempotency, consistency and failure handling, data modeling, APIs, observability, fraud detection, and compliance.