Design a subscription management system for Khatabook.

A subscription management system for Raisin should enable users to seamlessly browse, subscribe to, and manage financial products such as savings accounts or investment plans offered through partner banks. The system must support secure user authentication, KYC verification, and real-time integration with third-party banks for initiating and renewing subscriptions. It should track each subscription’s lifecycle—including status, term dates, and transaction history—while also handling automatic renewals, cancellations, and user-triggered changes. Notifications (via email, SMS, or in-app) should alert users about upcoming renewals, expirations, or product updates. The backend should be built on a scalable microservices architecture using secure APIs, event-driven messaging (e.g., Kafka), and a relational database for strong consistency. Compliance with financial regulations (e.g., GDPR, MiFID II), encrypted data handling, and audit logging are essential. An admin dashboard should provide internal teams with tools to monitor subscriptions, handle exceptions, and support customer inquiries efficiently