ArgoCD

ArgoCD is the GitOps standard for Kubernetes — push a manifest to Git, and ArgoCD ensures your cluster matches. It has a genuinely useful web UI that shows deployment status, diff views, pod logs, and sync state across all your applications. 60% market share in GitOps tools for good reason.

If you're deploying to Kubernetes and want declarative, auditable deployments, ArgoCD is the default choice. Flux CD is the modular alternative — lighter, better for massive scale (1,000+ apps), but no built-in UI. Jenkins is what you're replacing. Spinnaker is the enterprise option nobody loves but many enterprises use.

The catch: ArgoCD is Kubernetes-only — no deploying to bare metal, VMs, or serverless from here. The ApplicationSet controller for multi-cluster deployments adds complexity. Helm chart rendering can be slow for large charts. And ArgoCD's UI, while excellent for observing, doesn't replace proper CI — you still need GitHub Actions or GitLab CI for building and testing. It's CD, not CI/CD.