A service mesh is an essential infrastructure layer for managing communication between services in containerized microservices applications, ensuring secure, reliable, and fast interactions. Comprising a data plane and a control plane, it decouples network management from application code, facilitating observability and network management without altering the application's core functionalities. Service meshes became prominent with the rise of microservices architecture, providing critical features such as service discovery, load balancing, TLS encryption, and traffic management. This infrastructure layer supports diverse programming languages and frameworks, enabling teams to focus on business logic while DevOps ensures service reliability. Popular open-source service mesh solutions include Linkerd, Istio, Consul, and Kuma, with the potential for future innovations like eBPF to further enhance service communication.