The Service Mesh Interface (SMI) is a Kubernetes-native specification that defines a standard set of APIs for service meshes, aiming to provide a common, portable set of service mesh APIs for users to use in a provider-agnostic manner. The SMI does not include a service mesh implementation but rather serves as a specification for service mesh implementations to follow. This standardization helps simplify the development process and reduces integration complexities with other technologies and tools. The SMI API includes four main components: Traffic Specs, which allows defining routes; Traffic Split, which enables traffic splitting and shifting methods like A/B testing and canary deployment; Traffic Access Control, which sets access control policies for pod-to-pod communications based on service proxy identity; and Traffic Metrics, which collects metrics on HTTP traffic. These APIs help manage, secure, and observe service-to-service traffic within a cluster, promoting resilience and reducing the complexity of service mesh technologies.