How yaml validator works
A YAML validator parses your document against a YAML parser and reports either that the document is valid or the first syntax error it hit, with a line number. This catches the common YAML mistakes: inconsistent indentation, a missing space after a colon, a tab used for indentation, or an unbalanced flow collection.
When the document is valid, the tool also re-serializes it as clean, canonical YAML: consistent two-space indentation, dash-prefixed lists, strings quoted only where required, and empty containers as [] and {}. This normalizes messy hand-edited YAML into a stable canonical form you can diff and commit.
Everything runs in your browser using a built-in YAML parser (no external service), so your configuration never leaves your device. Use it to sanity-check a CI pipeline file, a Docker Compose file, or a Kubernetes manifest before you commit it.