YAML syntax
Updated 2026-02-15
YAML basics for configs: keys, lists, multiline strings, and anchors. GitHub Actions, Docker Compose.
Basics
key: value. Indent with spaces (no tabs). Lists: - item or [a, b]. Nested: key:\n sub: val. Strings: quoted if special chars; | multiline literal, > folded.
Anchors and reuse
&anchor name: value. *anchor references it. Useful in GitHub Actions and Docker Compose for repeated blocks.