Design multi-region banking data synchronization
Company: Revolut
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
## System design: Global bank with multi-region data consistency
A digital bank operates in multiple geographic regions (e.g., EU, US, APAC). Users can log in and perform operations (balance checks, transfers, card payments) from anywhere.
### Prompt
Design a data architecture that keeps customer/account data consistent across regions.
### Requirements
- High availability and low latency for reads (users worldwide).
- Correctness for money movement (no double-spend).
- Tolerate regional failures and network partitions.
- Clear consistency model: what must be strongly consistent vs what can be eventually consistent.
### Discuss
- Replication strategy (sync/async, leader-based vs multi-leader).
- How to handle cross-region writes (especially transfers).
- Conflict resolution and idempotency.
- Operational concerns: recovery, reconciliation, auditing, observability.
Overview: This question evaluates competency in distributed systems and data consistency for financial applications, emphasizing replication, transaction correctness, conflict resolution, idempotency, and operational resilience.
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