A hyperscale fintech company, initially focused on credit card bill payments, expanded its ecosystem to include rewards, rent payments, short-term credit lines, and investment access, resulting in over 10 million high-credit-score users. Their original data platform, built on Amazon DynamoDB, struggled with performance and cost issues as the company grew, affecting real-time use cases like user experience optimization, fraud prevention, and campaign targeting. To address these challenges, the company migrated to Aerospike, which provided a scalable foundation capable of sub-millisecond response times, reducing infrastructure costs by 75% and read latency by 88%. The migration was executed with zero downtime, transitioning from high-concurrency reads and duplicate state issues to predictable performance and cost efficiency. Aerospike's architecture allowed the company to improve real-time personalization and campaign operations, providing near-instant results for campaign reach calculations and continuous updates to user data. This shift enabled the fintech to enhance campaign performance analytics with real-time feedback, leveraging integration with Apache Flink and Kafka, ultimately transforming the data infrastructure into a unified platform that supports multiple product lines with lower overhead and consistent performance.