Overview As modern applications require greater scalability, resilience, and responsiveness, traditional REST-based architectures are hitting their limits. This article looks into how Spring Boot developers can upgrade their APIs from synchronous REST calls to asynchronous, event-driven communication through an event mesh that utilizes technologies like Kafka, RabbitMQ, or NATS. It emphasizes important architectural differences, design patterns for decoupling services, and practical implementation strategies in Spring Boot.