Argo CD implements the GitOps pattern for Kubernetes deployments, using Git repositories as the source of truth for defining the desired application state. It continuously monitors running applications and compares their live state against the desired state specified in Git.
Key features include automated sync policies, rollback capabilities, multi-cluster management, SSO integration, webhook-based triggers, and a web UI for visualizing application topology. It supports Helm charts, Kustomize, Jsonnet, and plain YAML manifests.
As a CNCF graduated project, Argo CD has a thriving community and ecosystem. It's free and open source under the Apache 2.0 license.