YAML (YAML Ain't Markup Language)

YAML is the configuration language of modern DevOps. GitHub Actions, Docker Compose, Kubernetes manifests, Terraform, and dozens of other tools use YAML files to define how things should be built, deployed, and run.

YAML uses indentation (spaces, never tabs) to show hierarchy, making it visually clean but sensitive to formatting. A misplaced space can break an entire deployment pipeline. Keys and values are separated by colons, lists use dashes, and strings usually do not need quotes.

For vibe coders, YAML is one of the formats AI handles well. You can describe a CI/CD pipeline in plain English and get a working YAML file. The key skill is reading YAML to verify structure, catch indentation errors, and understand what each section does before pushing it to production.