System designHardsd-g199

Subject Multi regionLevel Senior–Staff~50 minCommon in Distributed systems interviewsIndustries Technology, Software development

Question

Design a multi-region payment ledger for a global checkout platform processing 8k authorizations/sec across three regions (US, EU, APAC). Money movement must be exactly-once and auditable; EU cardholder data must stay in-region (PSD2/GDPR). Reads (balance/history) are 20x writes and tolerate a few seconds of staleness, but a captured charge must never be double-captured even during a regional failover. How do you partition the ledger, place writes, and keep the books correct across regions?

What a strong answer looks like

Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts — data model, bottlenecks, consistency, failure modes — and name the trade-offs you are making.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.