This article describes how Amazon Finance Technologies built a scalable, event-driven remittance notification service using Amazon DynamoDB to handle 42 million annual payments across 150 countries.

• DynamoDB selected for seamless scalability and schema flexibility for diverse payment scenarios
• On-demand capacity mode handles variable payment volumes without capacity planning
• Enrichment service receives banking partner confirmations and enriches payment data
• Notification service sends customer notifications using enriched payment information
• DynamoDB Streams trigger Lambda functions to process change data capture events
• Sweeper pattern uses sparse GSIs to identify and retry failed workflow jobs
• Optimistic locking via versionId prevents duplicate processing across multiple processes
• Step Functions run ARN generated upfront prevents accidental reruns and duplicate processing
• Solution reduced development effort by 40% compared to alternative database options

Amazon FinTech leveraged DynamoDB's native features to build a resilient, event-driven remittance system handling high-volume payments with minimal operational overhead.