The whitespace-sensitive serialization format that became the lingua franca of Kubernetes manifests, CI configs, and infrastructure-as-code.
YAML (YAML Ain't Markup Language) is a human-readable serialization format whose syntax uses indentation rather than braces or tags. It's the default config format for Kubernetes, Helm, Argo, GitHub Actions, GitLab CI, Ansible, and most cloud-native tools. The strengths are readability and merge-friendliness; the weaknesses are well-known footguns, the Norway Problem (`country: NO` parses as boolean false), tab-vs-spaces ambiguity, multiline-string subtleties, and the entire 'YAML 1.1 vs 1.2' compatibility maze.
If you operate Kubernetes, you operate YAML. The footguns are not theoretical, deploys have failed because `version: 3.1` parsed as a float and lost trailing zeros, services have broken because a country code parsed as a boolean. Tooling that lints, schema-validates, and renders Helm/Kustomize output before commit is the difference between YAML being a productive substrate and a perpetual source of subtle outages.
See the part of the platform that handles yaml in production.