Transitioning to a microservice architecture introduces challenges such as managing the network and maintaining observability, which can be addressed by implementing a service mesh. A service mesh serves as a dedicated infrastructure layer that facilitates secure, quick, and reliable communication between services in containerized and microservice applications, decoupling the microservices from network management, thus allowing engineering teams to focus on developing services. Originating with Linkerd, service meshes use a sidecar model, consisting of a data plane with proxies and a control plane for management, to handle communication, monitoring, and security. They provide essential services like load balancing, service discovery, encryption, and observability, making them a vital component for modern cloud-native applications. Recognizing the need for a service mesh involves considering factors such as diverse programming languages, reliance on third-party code, and the need for high visibility for security or compliance. Koyeb integrates a built-in service mesh feature into its serverless platform, enabling developers to efficiently connect, secure, and observe microservices, thereby optimizing microservice architecture without diverting resources from business-specific services.