The client encountered difficulties in creating a scalable real-time notification system to effectively support a growing user base. Their existing approach, based on traditional polling mechanisms, resulted in high system load, inefficient resource usage, and delays in events/notifications, which adversely affected user experience. As the number of users increased, the system's ability to handle concurrent requests diminished, restricting both scalability and performance.

The client is a leading global investment management firm, offering comprehensive solutions to institutions, financial professionals, and millions of individuals around the world.

• Scalability Challenges: Solution required which is capable of efficiently handling real-time events as their user base grew.
• Resource Inefficiency: Traditional polling methods resulted in high system load and inefficient use of resources, impacting overall performance.
• Delayed Notifications: The inability to deliver real-time updates caused significant delays in notifying users of critical events, negatively impacting user engagement and satisfaction.
• Limited Simultaneous Request Handling: The existing system struggled to manage high volumes of concurrent requests, affecting scalability and reliability.
• Integration and Growth Needs: A robust, maintainable architecture was essential to integrate seamlessly with existing microservices while supporting future scalability.

To solve the client’s challenges, we built a scalable, reactive real-time notification system using modern technologies. Leveraging Server-Sent Events (SSE) and the Spring Boot Reactive framework, we implemented non-blocking, asynchronous communication to optimize resource usage and reduce system load. Redis Pub/Sub acted as the message broker to efficiently handle high concurrent requests and ensure real-time delivery. The solution was seamlessly integrated with the client’s microservices, providing a robust, maintainable, and scalable architecture for future growth.

• Reactive Architecture: Implemented a non-blocking, asynchronous communication model using Spring WebFlux for real-time updates.
• Message Brokering: Utilized Redis Pub/Sub to enable efficient handling of high concurrent requests and immediate message delivery.
• SSE Protocol: Adopted SSE for persistent client-server connections, eliminating the need for constant client polling.
• Scalability Focus: Designed the system to seamlessly scale with the client’s growing user base and increasing notification demands.
• Microservices Integration: Ensured smooth integration with the client’s existing microservices for a unified and maintainable architecture.

• Scalability: The reactive architecture supports handling a growing user base efficiently without compromising system performance.
• Resource Optimization: Non-blocking, asynchronous communication reduces system load and maximizes resource utilization.
• Real-Time Notifications: SSE ensures instant delivery of notifications without the need for continuous client polling.
• High Concurrency Handling: Redis Pub/Sub efficiently manages high volumes of simultaneous requests, ensuring seamless message delivery.
• Seamless Integration: The solution integrates smoothly with the client’s existing microservices, ensuring easy maintenance and future scalability.

In conclusion, the implemented solution effectively addressed the client’s challenges by providing a scalable, resource-efficient real-time notification system. By leveraging reactive programming, SSE, and Redis Pub/Sub, we ensured optimal performance, real-time delivery, and seamless integration with the client’s microservices. This robust architecture not only met the current demands but also supports future growth, enhancing both scalability and user experience.