While the concepts are universal, you need a tool to implement the pull-based model. The two undisputed leaders in the Kubernetes space are ArgoCD and Flux. Both are graduated projects under the Cloud Native Computing Foundation (CNCF), meaning they are production-proven and have strong community backing.
ArgoCD
ArgoCD is famous for its excellent Graphical User Interface (GUI). It visualizes your applications, their current sync status, and shows you exactly what has drifted between Git and the cluster — down to the individual field level. It treats an Application (a CRD) as its primary unit of management, where each Application maps a Git path to a cluster namespace.
ArgoCD is often easier for teams new to GitOps because the visual feedback makes the reconciliation loop tangible. You can see in real time whether your app is "Synced" (Git matches cluster), "OutOfSync" (drift detected), or "Degraded" (resources are unhealthy).
An ArgoCD Application CRD names the Git repository, branch, and path to watch, the destination cluster and namespace to deploy into, and an optional syncPolicy.automated block enabling prune (delete resources removed from Git) and selfHeal (automatically revert manual changes) — the settings that turn on the self-healing behavior described earlier.
Flux
Flux is a more "native" Kubernetes experience. It has no built-in GUI (though Weave GitOps provides one). It relies entirely on Custom Resource Definitions (CRDs) like GitRepository, Kustomization, and HelmRelease. It is designed to be highly composable and fits well into clusters managed entirely via YAML and automation.
Flux's equivalent Kustomization CRD expresses the same idea: a reconciliation interval, the path in the repo to watch, prune to remove deleted resources, a reference to the GitRepository source, and the target namespace.
Choosing between them: ArgoCD wins on visibility and ease of onboarding. Flux wins on composability and GitOps-native design. Many large organizations use both — ArgoCD for application teams who want a UI, Flux for platform teams managing cluster infrastructure. Both support Helm, Kustomize, and notifications.