Kyverno runs as a [dynamic admission controller](https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/) in a Kubernetes cluster. Kyverno receives validating and mutating admission webhook HTTP callbacks from the kube-apiserver, applies matching polcies, and returns results that enforce admission policies or reject requests.
Mutating policies can be written as overlays (similar to [Kustomize](https://kubernetes.io/docs/tasks/manage-kubernetes-objects/kustomization/#bases-and-overlays)) or as a [JSON Patch](http://jsonpatch.com/). Validating policies also use an overlay style syntax, with support for pattern matching and conditional (if-then-else) processing.