This research migrates a monolithic smart intercom system to a microservice architecture, making the system more secure, stable, and scalable. The security mechanisms of the instant messaging platform are combined with microservices to improve the security of the system. The stability and performance of microservices are shown to be better than those of monolithic services through experimental tests. Residents can use different instant messaging software instead of the handset to improve the convenience of using this system. This system also implements community broadcasts, platform broadcasts, unit broadcasts, and family broadcasts to exchange messages across different instant messaging platforms. This paper proposes OpenAPI for other smart intercoms to integrate this system’s services and resources. In addition, this study deploys two microservice architectures using a native load balancer with a kube proxy and a service mesh load balancer with an istio proxy. Experiments were conducted during which residents tested the kube proxy and the istio proxy using stress testing tools on two microservice architectures, and the results showed that the kube proxy was slightly better than the istio proxy.