kargo

Kargo orchestrates that promotion pipeline. Consider it a GitOps-native way to move application versions through stages with approval gates and verification steps.

Apache 2.0, Go. Built by the creators of Argo CD. Kargo doesn't replace your CI. It sits on top of your GitOps tools (Argo CD, Flux) and manages the lifecycle of getting a change from one environment to the next. It watches for new container images or Helm chart versions and can auto-promote or require manual approval. Fully free and open source. No paid tier currently. Akuity (the company behind it) offers a managed Argo CD platform but Kargo itself is free to self-host.

Self-hosting requires a Kubernetes cluster (it runs as a controller). Setup is straightforward if you already have Argo CD running. Ops burden is moderate. It's another controller to monitor. Solo: overkill unless you're learning GitOps. Small teams with multiple environments: this is where Kargo starts making sense. Medium to large: strong fit for managing promotion across many services.

The catch: it's young. The API is still evolving, documentation is thin in places, and you're locked into the GitOps model. If you're not already using Argo CD or Flux, adopting Kargo means adopting GitOps first.